# carb/intake selection



## Thurber73 (Mar 7, 2013)

I've got a stock 350 in my LeMans and looking to upgrade the intake and carb. I've pretty much decided on the Edelbrock performer series 2156 low rise. I have been looking at Holley 650 cfm carbs, does anyone have a suggestion as to which one I should go with?? Looking primarily at 0-80783c (4150) and the 0-80555c (4175)


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## maktope (May 22, 2013)

I just picked up edelbrock performer rpm duel plane intake. I went with their carb thunder avs 800cfm. Can't give you a review since it's not on yet. Ran into problems installing headers. Got next two days off and no rain in forecast if I get it on ill let you know.


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## BearGFR (Aug 25, 2008)

What's on it now?

Hint: On a stock, or near stock engine there is nothing that will out-perform a factory cast iron 4bbl intake with a properly set up Quadrajet, or a tri-power. Period.

All the aftermarket "pretties and shineys" are just that. Pretty and shiny. But they're also slower.

Bear


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## PontiacJim (Dec 29, 2012)

I second that with Bear. The factory quadrajet cast iron manifold has been proven time and time again to be one of the best picks, especially with a stock or mildly modified engine. Invest in a good replacement Q-jet carb. Small primaries bores are great for gas mileage. Kick those big secondaries in for power - and a sound you won't get with the Holley you are thinking about. The Q-jet is rated at 750 CFM or the later 800 CFM. I installed one on my 1976 Lemans which was a factory 2 barrel 350 CI. More power, awesome sound when the secondaries opened up, and could get 21 MPG cruising at 70 MPH with stiff (as I recall) 2.73 or such. Use a good after market open element air cleaner - the bigger the better.

Just my opinion on this one.


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## Thurber73 (Mar 7, 2013)

It is a Rochester 2G with divorced choke, and the stock 2 barrel manifold. Most things I have read say that the Q-jet is a tricky/temperamental bitch.


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## Thurber73 (Mar 7, 2013)

Also the smallest Q-jet I have seen is a 750 cfm which by any of the calculators is more carb than needed based on cubic inches and rpm without any other mods.


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## ALKYGTO (Mar 29, 2010)

The Qjet will work fine on your 350. They even used them on the OHC six. Many Chevy 350's, Olds 350's and Pontiac 350's and 326's came with the Qjet. When they are right they work amazing. Great throttle response and fuel economy. Usually it is the accelerator pump and/or throttle shaft bushings that give them the notorious bog. Also stay away from the later "electronic" Qjets, they are the only ones that have wires going to them so they are easy to identify. I much prefer a Qjet to the Carter AFB or Thermo-quad. 

Find yourself a good core and contact Cliff Rugles to get it redone( if it needs it). 

Cliffs High Performance Quadrajets :: Qjet Carburetor Rebuild Kits, Parts, Quadrajet Rebuilding, Quadrajet Parts, Bushing Kits, Carb Tuning


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## BearGFR (Aug 25, 2008)

I will admit that in order to make a QJet run well you do have to know what you're doing and think a little bit. My 69 GTO is an honest 11-second street car (best so far, 11.86 @ 113 mph) that I also drove on the full Hot Rod Power Tour this past summer - all 2300 miles of it (there and back). It has an 800 cfm QJet. 

Don't believe everything you read out there on the Inter-tubes. Even here. :nono:

Bear


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## PontiacJim (Dec 29, 2012)

As Bear stated, 750 CFM is not too big. Same as I had on my stock 350 I mentioned earlier. You can get a good rebuildable core cheap at most car swap meets if you go to these. Ebay has quite a few and one up there now is a rebuilt NAPA Q-jet for $111.00. There are many more cheaper that need rebuilding. You want to make sure you get the Rochester Q-jet and not the Carter. You also need to make sure that you get a Pontiac Q-jet so your carb/gas pedal cable will work with it.

Saw a video that was 16 minutes long on the web on rebuilding the Q-jet. Might give you and idea of what you are getting into OR as Bear suggested, either contact Cliff Rugles for a rebuilt unit, price on having your core rebuilt, or parts to rebuild yours. Shop around a bit. It is really not all that difficult a thing to rebuild. There are also several how-to books on the market on how to rebuild the Q-jet. You will find most members here advise any Pontiac Performance enthusiast to get a copy of Jim Hand's book How to Build Max Performance Pontiac V-8's. You can get it on Amazon.com and it has a section on Q-jet rebuilding and modifications.

You should be able to get a cast iron Q-jet intake cheap at a swap meet, craigslist, local trade paper, etc.. If it were me, I would not pay more than $25 for a Q-jet rebuilder core and then go through it -but I know what to look for and how to rebuild them so that's to my advantage. Last swap meet I was at had a ton of them in the $15 -$25 range. You can always get a cheap one, tear it down to see what your getting into and then decide what you want to do. Its all about fun and learning.


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## Icefan71 (Apr 7, 2011)

These guys are steering you in the right direction. I swapped out my 2 bbl Rochester for a cast iron 4bbl intake and a Qjet. I bought Cliff's (of Cliff's High Performance) Qjet rebuild book, then I bought a rebuild kit, jets, rods, hardware from him. I told him what I had and he was able to sell me exactly what I needed. This was my 1st rebuild so it took me some time and I made many mistakes. But after all my screw-ups, I can easily take one apart and put it back together with confidence.


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## Thurber73 (Mar 7, 2013)

Since my last post I talked to the people at Butler Performance and they suggested I go with the Edelbrock 2156 Performer intake and the Holley 4175 0-80555c(which is a Qjet replacement). They said it was a good combination. I am not ruling anything out or knocking anyone's setup, just trying to gather info and be a little informed hopefully before I make any purchases.


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## Thurber73 (Mar 7, 2013)

checking out the link to Cliff's High Performance now.


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## PontiacJim (Dec 29, 2012)

The people at Butler know Pontiacs, so you can put stock in their suggestions. The factory intake and Q-jet is just an option or suggestion because it is a great factory piece that works well, and sometimes better, than aftermarket pieces. For us who do a lot of our own work and build/rebuild our rides, the factory combo saves money and we know the ins and outs of rebuilding a carb.

That said, buying a new intake and carb is a simpler bolt on/no fuss installation. The aluminum intake looks good when you pop the hood. I suggest you find a clear coat that is made for your intake to preserve the finish. The manifold unprotected will oxidize and dull out. Top it off with a nice big open element air cleaner with chrome top, and you have a nice look. Dress your engine up with chrome valve covers, some nice spark plug wires and wire looms, and you'll have a sharp looking engine.

Keep us posted on your results. If you go with the Holley and Performer, make sure you come back with a post (maybe a photo or two), even if it is weeks from now, to let us know how the combo works on your application, any problems encountered, and how the car's performance has improved. This way, the forum has your post to reference in the future if another reader is seeking the same advice or application.


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## Thurber73 (Mar 7, 2013)

I found someone local with a Rochester Quadrajet supposedly functioning for $100.00. He says the #'s are on the main body GM 17054779 and on the front 17053289 and there is a circle with a # 6 in it and to the side of that a #9. It has electric choke and a side fuel inlet. Or is there a resource I can consult?

Can anyone decode the #'s and let me know if this is on I should be interested in?
Or is there a resource I can use to find out?


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## Thurber73 (Mar 7, 2013)

I found the casting # chart at Cliff's High Performance but not sure which of the above 1705 #'s I should use in decoding.


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## chuckha62 (Apr 5, 2010)

You could use that, but being that it is for a '77 Chevy, the inlet comes in from the passenger side, instead of the front like a Pontiac carb. You can do better for less money, I'm sure. 

The thing with a Quadrajet is that it's only as good as the last guy who worked on it. It's a VERY good carb and you will not do better (or any where near as well) with the other combinations you've thrown out so far. Unfortunately, they're complicated and guys do stupid things to them trying to out think the factory. Cliff wrote the book on Quadrajets (literally!) And if you follow his advice and give him a call, he'll walk you through it and you'll have a trouble free carb that will last for years.

$.02

Chuck


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## PontiacJim (Dec 29, 2012)

Found a website Carburetor Parts & Kits for Carter, Ford Motorcraft, Holley & Rochester Carburetors which decodes the carb. Seems to be a 1975-1979 carb, but you want to be sure it is a Pontiac 350, 400, 455, and not a 301CI.

You may also want to make sure the carb is for an automatic versus a manual transmission as there may be some differences in linkage as you may need an attachment for your kickdown cable to the transmission. Not sure on this, but looking at different Q-jets on Ebay. Look at your throttle linkage brackets to match up.

NAPA used to carry a master list of Q-jet carb numbers that could identify the carb as well.

Just found a blog that says the 17054779 in a circle is the main body part number and not the carb number, 17053289 was the part number for the top, and there was another number "17057502" on the side near the throttle linkage. THIS seems to be the ID number location, so get that number from the seller and see what it is. If the carb has the same numbers as what I have found here, 17057502, it was a 1977 Chevy Q-jet 350 CI 180 HP, AT.


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## rexs73gto (Nov 25, 2012)

I have my 73 GTO that has had several carbs & 5 different engines in it over the life of the car. I now run a 462 with E-heads a performer RPM intake a RA IV cam (crane blue print) SRP forged pistons & eagle H-beam rods. I have tried several crbs with this combo, a 750 Holley HP carb, an 800 duel feed Holley, & am here to say I am back to my Q-jet. I run a 79 800 cfm Q-jet that I have played with & has some of the tricks from cliffs book in it to. My car is 3650 lbs & haS 3:73 rear gears & I run consistant 11:50's. I have had very good luck with the Q-jets over the years. One thing you have to remember is the Q-jet is a carb that adjusts the fuel needed & air by itself as needed by the demand. Thats why they can use them on so many different engines from a 6 cylinder to the biggest V-8 around & it still tuns great. Use the Q-jet , but buy Cliff Ruggles book about Q-jets & read it from cover to cover & then rebuild your Q-jet for your car. You'll be very happy when you decide to go with a Q-jet.


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## Thurber73 (Mar 7, 2013)

What should I expect to pay for a cast iron 4 barrel intake? If the $100 is not good for the Qjet what is the going rate and those as well?


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## chuckha62 (Apr 5, 2010)

Thurber73 said:


> What should I expect to pay for a cast iron 4 barrel intake? If the $100 is not good for the Qjet what is the going rate and those as well?


I probably got lucky, but I bought a date code correct (2 weeks prior to my motor date) intake for $125.

It's odd talking about paying 100 bucks or more for a Quadrajet, since we used to be able to pick them up all day long for $5-$10. It's not that $100 is too much these days, but you really want a Pontiac carb if you can get one, since the inlet needs to come in from the front, not the passenger side.

Other guys can tell you for sure, but Cadillac and Buick/Olds may have a front inlet, too. Check Craigslist, Ebay, swap meets, etc. And I'm sure you'll find what you're looking for.

Chuck


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## Thurber73 (Mar 7, 2013)

Curious about the push for a Pontiac Qjet...can't you just bend up a new fuel line or get an elbow to make the connection to the carb from the side? Or are the carbs calibrated differently between chev, pontiac etc....?


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## 68Resto-mod (Nov 10, 2009)

If you want to use the stock fuel line from the pump to the carb, you must use as Pontiac Q-Jet. My neighbor actually GAVE me a re-manufactured Q-Jet. The code says it was from a 77 Chevy (Corvette perhaps) with automatic. 

Just because it says “Re-manufactured” on the box doesn’t mean it was done correctly. I bought Cliff’s book and did the re-build myself. Before starting, I gave him a call and he helped choose the correct “recipe” (as per his book) for my engine setup. He even handpicked the parts for one of his high performance rebuild kits I bought from him. You only need a few basic tools and a set of really small drill bits. Oh yah, and a lot of patience, read the book about three times, take your time and follow the carb setup instructions that come with Cliff’s kit to the letter.

I drove the car for the first time last weekend. Awesome throttle response, smooth idle and I haven’t done any tweaking on it yet. Could not open the secondary’s since my test drive was confined to my small development. 
I solved the side inlet issue by cutting the fuel line from the pump and installing a braded fuel hose. See picture attached.

PS. Using stock intake with mild porting/gasket matching. Tests have shown that there is little if any advantage in using an Edelbrock intake except for weight savings. (As per the book written by Jim Hand).


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## chuckha62 (Apr 5, 2010)

Thurber73 said:


> Curious about the puswr a Pontiac Qjet...can't you just bend up a new fuel line or get an elbow to make the connection to the carb from the side? Or are the carbs calibrated differently between chev, pontiac etc....?


Just trying to give you the benefit of many years of experience. You have the opportunity to do it right. Why not take it?

I learned MANY years ago that I'm too poor to buy cheap and or to buy twice. I would rather take the time and research up front (such as asking guys who've been there and done that) and ultimately do it right the first time.

Will the Chevy work? Sure! Will it take more work? A little. Are you safer using prebent factory hardlines and factory flared fittings to prevent a potential fire later? ABSOLUTELY!

Do yourself a favor and take the time to do it right. You won't be sorry!


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## ALKYGTO (Mar 29, 2010)

Good God that is a beautiful engine. Well done sir! :thumbsup:

I gotta ask though......what is the deal with the rusty thermostat housing?!?:leaving:


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## 68Resto-mod (Nov 10, 2009)

That picture is several months old. Old thermostat housing has been replaced with new aluminum housing. That rusty old thing had to go. Thank you for the compliment.


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## Thurber73 (Mar 7, 2013)

Just ordered Jim Hand's book...what is with the huge price variations on this thing? It goes anywhere from about $18.00 to several hundred, also I saw the book has been replaced with one of the same name but written by Rocky Rotella. Any idea what difference in the books is?


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## Thurber73 (Mar 7, 2013)

Does anyone have any experience with the Q-jets from SMI Carburetor and if so what do you think of them? They have a 800 cfm Pontiac Qjet for $375.00, its a Stage 1 which is setup for a stock 350 like mine.


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> Just ordered Jim Hand's book...what is with the huge price variations on this thing? It goes anywhere from about $18.00 to several hundred, also I saw the book has been replaced with one of the same name but written by Rocky Rotella. Any idea what difference in the books is?


Two different books and two different authors. Amazon.com is where you will get your best deal. Just checked Amazon, holy crap, $40. Too much for a soft cover. Probably because they are out of print at this time. I would shop around on the internet. Would not pay anymore than $20 because I'm cheap. I would buy "How to Rebuild and Modify Rochester Quadrajet Carburetors" by Cliff Ruggles used for $14.00 and up, or new if you prefer. Rock's book would be great for engine rebuilding as well. He is a regular contributor for the monthly Pontiac magazine found at your local magazine rack.


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> Does anyone have any experience with the Q-jets from SMI Carburetor and if so what do you think of them? They have a 800 cfm Pontiac Qjet for $375.00, its a Stage 1 which is setup for a stock 350 like mine.


Not me. The price seems OK when I looked at comparative prices on Ebay. If you choose to go rebuilt, which is also an option, then just make sure you get a warranty or guarantee with it. No doubt they do check them thoroughly. What I always do is check the internet but put the word "complaints" before whomever the product seller is and then see if you find a lot of negative feedback on the product. If they are not a good company, the internet will let you know. Just do some comparing and then call the guy and talk with him or ask questions, most of them will talk or email you. Make sure it will fit your application, so give them all the specifics.


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## Thurber73 (Mar 7, 2013)

thanks Jim, I got my Jim Hand book ordered and should be here Monday ($18.00 with shipping included) I know that OPGI carries the SMI carbs. but they are marked up a little more than getting from SMI. I am looking to do a bolt on carb if I can afford it just for the ease and asthetics, I rebuilt my Rochester 2GV that is on the car now which wasn't too bad by following multi step videos on youtube from Mike's Carburetor shop.


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## Thurber73 (Mar 7, 2013)

I would like to say thanks PontiacJim, BearGFR, Chuckha62 and everyone else who has contributed and shared their experience and knowledge with me. I am carefully reading and taking in all of your responses. If anyone is in the Cleveland area I would be happy to buy you a beer.


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> I would like to say thanks PontiacJim, BearGFR, Chuckha62 and everyone else who has contributed and shared their experience and knowledge with me. I am carefully reading and taking in all of your responses. If anyone is in the Cleveland area I would be happy to buy you a beer.


We all try our best to help based on our experiences, knowledge, and resources. The main thing is to have fun and keep alive a little piece of history, and legend. Whatever you decide, please return to this thread and let us know what you decided, what you installed, and your seat of the pants evaluation......and maybe a photo or two.


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## Thurber73 (Mar 7, 2013)

After all the input I got from you guys and reading the Jim Hand book I am convinced about the stock intake and Qjet being the best way to go. The Qjet is not a problem to find but I have searched all over the interweb for the Intake manifold and no luck except ones that way across the country and on Craigslist. I am sure if I send someone the money first they will ship me the part right?? lol ....any suggestions on finding part #9790140?


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## chuckha62 (Apr 5, 2010)

I would think that manifold would be available. Have you tried Frank's pontiac parts? I believe they're in Pennsylvania. He's got a pretty good online inventory and is pretty helpful by phone.

There's also a guy in Morgan Hill CA, named Kelly (I'm trying to remember his last name). I have his phone number somewhere and will PM it to you if I find it.

Keep up the search. The parts are out there!

Chuck


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## ALKYGTO (Mar 29, 2010)

Thurber73 said:


> After all the input I got from you guys and reading the Jim Hand book I am convinced about the stock intake and Qjet being the best way to go. The Qjet is not a problem to find but I have searched all over the interweb for the Intake manifold and no luck except ones that way across the country and on Craigslist. I am sure if I send someone the money first they will ship me the part right?? lol ....any suggestions on finding part #9790140?


Most of the Pontiac 4 bbl intakes are the same except for part #'s. I sold a member on here an intake for a Pontiac 350 that besides the part # was dimensionally the same as my factory 400 intake. I believe the mid 70's intakes are different as they have a "D" shaped secondary opening but even those will flow adequately for most applications. 

That said if the Q-jet will bolt up to a Performer I wouldn't be afraid to run that combination. A Performer will work fine for you and cut a little weight. I've only seen one vendor that sells an intake that is supposedly a direct reproduction of the Pontiac 4 bbl intake in aluminum and it was around $500.


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## BearGFR (Aug 25, 2008)

:agree Unless you're shooting for a perfect concours restoration, don't get hung up on part numbers. 

Bear


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## PontiacJim (Dec 29, 2012)

Find a local car show/swap meet. Get a copy of Hemmings Motor News at your local magazine/book store. They list car shows that may be in your area. Place your own "wanted" ad in your local auto paper. Sometimes some guys have these things just hanging around and don't figure anyone is interested or wants a cast manifold because everyone want and aluminum intake. Check your local junk yards and ask if they might know where to find one. Check the local engine machine shops, they often know a lot of customers and can possibly direct you to a "buddy" who has one. Same on the carb. I was just at a car show in Myrtle Beach, SC that had a small swap meet and there were a couple dozen Q-jets of different makes out on the tables. I don't know if Olds, Buick, Caddy, might work as far as linkage hook-ups and fuel line placement. If any do, then you have a lot more options than just Pontiac.

Also, you might consider joining POCI (Pontiac-Oakland Club International). I used to be a member years ago and they had parts for sale & wanted in their newsletter.

Again, best bet will be a good swap meet, even if you have to drive a bit to get to it. Local hot rodders should know where & when these are. Check the internet for your area as well. Then you can see exactly what you are buying and even haggle on the price. Just know what you are looking for and you should have no problem. $25 or so should get you a good Q-jet core and I would not pay anymore than $50 for a factory 1965-1974 intake.


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## PontiacJim (Dec 29, 2012)

Check out the article on Q-jets that gives the Pontiac year/carb number for the Q-jet. This will be helpful in your search. Keep a copy for reference.

highperformancepontiac.com, and search for the article titled "Rochester Quadrajet Carburetor - Quadrajet Quotient - Junkyard - Crawler Tech". Page 4 has the numbers and years.


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## Thurber73 (Mar 7, 2013)

Thanks guys, I am open to other year/part # intakes...of course the correct one would be ideal but not a must have. Continuing the search I will keep you posted on what I find or don't find.


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## Thurber73 (Mar 7, 2013)

I just found locally a 9794234 date code D029 intake manifold for $50.00. Its been beed blasted and painted, the photos look nice. The Qjet I have not seen and don't know the condition of but the guy is talking like $80.00 for the carb. anything I should watch out for with either of these items?


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## chuckha62 (Apr 5, 2010)

Has the manifold been magnafluxed? If not, take it to a machine shop and have it done. They tend to crack between the left and right side under the carb base. 

Chuck


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> I just found locally a 9794234 date code D029 intake manifold for $50.00. Its been beed blasted and painted, the photos look nice. The Qjet I have not seen and don't know the condition of but the guy is talking like $80.00 for the carb. anything I should watch out for with either of these items?


I have never experienced any manifold problems, but do give it a look over making sure gasket surfaces look good. Price is right on the manifold.

The carb, make sure it operates smoothly, looks fairly clean. $80 is a bit high even if it looks good - unless its been rebuilt or was recently running. I would haggle a bit and offer him $60 on the carb, and when he says no, how about splitting the difference at $70.00. Most will work with you on price.


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## chuckha62 (Apr 5, 2010)

Of the three I was offered, two were cracked right where I described. My machinist says he sees it all the time. It's fixable, but if you can avoid it, do so.


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## PontiacJim (Dec 29, 2012)

chuckha62 said:


> Of the three I was offered, two were cracked right where I described. My machinist says he sees it all the time. It's fixable, but if you can avoid it, do so.


Point taken. Its always a good idea to magnaflux and check for cracks on stuff as old as we see. I have learned from experience - don't buy a set of heads unless you can magnaflux, or get the seller to magnaflux them, before shelling out any cash. I am more than willing to compensate the seller the costs even if it turns out to be cracked. Rather lose $40 than $200. Same goes with the block. Most all components you can buy new, including the heads, or even a block, but this usually gets beyond most budgets - at least mine anyway.


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## Thurber73 (Mar 7, 2013)

Well the intake looked real nice, the carb is a little dusty from sitting on the shelf but it was rebuilt last year and everything moves freely. He gave me an extra rebuild kit for the carb that he had. I paid the $80 for the carb and he thru in a basic open element air cleaner as well as the rebuild kit so I figured good enough. I have some pics of the manifold I will try to post as soon as I figure out how to do that.


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## Thurber73 (Mar 7, 2013)

Here we go I think this will attach the pics


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## chuckha62 (Apr 5, 2010)

I think you've done well. Take your time on the carb and set it up according to Cliff's book. You're going to like the combination. 

Congrats!


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## PontiacJim (Dec 29, 2012)

Yep. looks good. Make sure you sand the paint off all sealing surfaces to not only remove the paint, but rough them up for the gasket to seal. I had the wonderful learning experience of leaving the paint on the gasket surface on my bother's 360 CI Mopar rebuild. The gasket slipped out, leaked water all over, and I had to pull it all apart and redo it. Paint is slippery! 

Did you get the carb as well or just the intake?


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## BearGFR (Aug 25, 2008)

Good job. 

Bear


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## Thurber73 (Mar 7, 2013)

The Qjet I got is the matching 1969 to the manifold apparently #7029270. I can't seem to find a new divorced choke thermostat any where, all I find are ones for a 2bbl. Does anyone know where I can get one?


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## Matthew (Feb 11, 2011)

Ames Performance has N139C 1968-70 4bbl Choke Thermostat Housing, Coil and Rod (AP) $37.00/ea. Matt


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## BearGFR (Aug 25, 2008)

If by thermostat you're talking about the"coiled spring in a box" that sits on top of the intake, I beleive they're all the same. i.e. no difference between 2bbl and 4bbl.

Bear


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> The Qjet I got is the matching 1969 to the manifold apparently #7029270. I can't seem to find a new divorced choke thermostat any where, all I find are ones for a 2bbl. Does anyone know where I can get one?


Check out a website called *Carbs Unlimited*. Click on the tab for "Parts". I just got some new parts for an AFB carb they listed. They list many parts for the Q-jet for rebuilding. If you don't see what you need, just email 'em and ask as I am sure they can help you. Should be easy enough to find one of them.


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## Thurber73 (Mar 7, 2013)

Thanks...I found the manifold mounted choke at Ames and ordered it along with some other items. My Cliff Ruggles book arrived Saturday and so far it is extremely detailed and also quite techy, I am going to read things over a few times to see how brave I am, its a bit more involved than the 2GV I rebuilt last year.


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## Thurber73 (Mar 7, 2013)

I have been finding conflicting things about which is the correct blue engine paint for 1968....anyone have an idea?

there is the greenish blue that the intake I bought has on it in the pics and I also have a can of Duplicolor (DE1616) that is a blue metallic which is a lighter silver/blue

this was the best source I could find..
http://www.pontiacpower.org/enginecolor.htm


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## chuckha62 (Apr 5, 2010)

'68 should be the Silver Blue Metallic.


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## Thurber73 (Mar 7, 2013)

ok thanx ....the silver blue is what I bought a while back before I double checked.


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## Thurber73 (Mar 7, 2013)

I finally put the stock intake and Qjet on my 68' LeMans 350 with 2 speed and A/C. I followed this attached drawing I found for the vacuum hookups...is this right? 

With this hookup my 2 speed trans is not down shifting when you stomp on the accelerator. I have the trans vacuum line hooked to a 3 nipple deal threaded in the backside of the carb. one straight out is for power brakes that I dont have yet and the other 2 come out the side one for the trans and the other is hooked to the #2 line from the TVS.


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## Thurber73 (Mar 7, 2013)

Here are some pics to go along with the above post.


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## Thurber73 (Mar 7, 2013)

Ok, figured out the downshifting problem...I had to change the throttle arm on the side of the carb and change the throttle cable bracket. Turned out the accelerator was not travelling far enough to engage the kick down switch on the back of the pedal. had to change the cable bracket because the on from my 2 bbl intake did not reach down to the intake bolt where it mounts.The throttle arm is what really did the trick allowing the cable to hook up properly and travel the way it should.


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> Ok, figured out the downshifting problem...I had to change the throttle arm on the side of the carb and change the throttle cable bracket. Turned out the accelerator was not travelling far enough to engage the kick down switch on the back of the pedal. had to change the cable bracket because the on from my 2 bbl intake did not reach down to the intake bolt where it mounts.The throttle arm is what really did the trick allowing the cable to hook up properly and travel the way it should.


And.......? Does this mean you got it running? If so, your opinion on the Q-jet as your final choice, good or bad? Hope you have an open element air cleaner or turned you factory lid upside down to get the famous Q-jet sound when those secondaries kick in.


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## chuckha62 (Apr 5, 2010)

Thurber73 said:


> Ok, figured out the downshifting problem...I had to change the throttle arm on the side of the carb and change the throttle cable bracket. Turned out the accelerator was not travelling far enough to engage the kick down switch on the back of the pedal. had to change the cable bracket because the on from my 2 bbl intake did not reach down to the intake bolt where it mounts.The throttle arm is what really did the trick allowing the cable to hook up properly and travel the way it should.


DOH! Forgot to tell you you needed a new throttle bracket. Actually encountered this myself at one time. The difference between the two and 4 barrel bracket is subtle.

Glad you got it figured out. How does it run? You should have been able to notice a big difference (although not huge, since you're still running the 2-bbl heads and cam).


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## ALKYGTO (Mar 29, 2010)

chuckha62 said:


> DOH! Forgot to tell you you needed a new throttle bracket. Actually encountered this myself at one time. The difference between the two and 4 barrel bracket is subtle.
> 
> Glad you got it figured out. How does it run? You should have been able to notice a big difference (although not huge, since you're still running the 2-bbl heads and cam).


OP needs Nitrous! :thumbsup: :tongue:















:leaving:


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## chuckha62 (Apr 5, 2010)

ALKYGTO said:


> OP needs Nitrous! :thumbsup: :tongue:
> 
> 
> 
> ...


That would definitely give it a bit more "seat of the pants" feel. :yesnod:


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## Thurber73 (Mar 7, 2013)

Sorry it takes so long to respond..Yep I got it running Chuck, its definitely got a better feel to it and its a bit smoother than the 2GV carb. No not huge difference though as far as power. I like the Qjet, I think I need to change the fuel pump because there is a difference in part #'s between the 2 and 4 barrel pumps...perhaps I am starving it a little with the wrong pump. Being that it is a 350 ci. what would be my best way to go for heads and cam?

thanks.
Jon


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## Thurber73 (Mar 7, 2013)

Being that it is a 350 ci. formerly a 2bbl now the 4 bbl what would be my best way to go for heads and cam?


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> Being that it is a 350 ci. formerly a 2bbl now the 4 bbl what would be my best way to go for heads and cam?


Personally, you don't want to mess with the heads unless you plan on doing a complete rebuild.

First upgrade, if you don't already have this -dual exhaust. Pontiacs need to breath and adding a good set of duals is a must. I like 2 1/2" pipes with the "X" crossover pipe, Dynamax mufflers.

My next upgrade at this time would be a shift improver kit in that 2-speed trans. This will give you a snappy shift and a tad bit more performance. They are inexpensive and not too difficult to install if you feel comfortable enough trying it. If not, a good trans shop can put the kit in.

As far as a cam, you can probably go a little better. Looking at the factory specs, you have 9.2 compression -which is perfect for todays gas. Your 2 bbl cam has a 269 intake duration, 277 exhaust duration with .376" intake lift/.412" exhaust lift. The 4bbl automatic HO version is 273/282 duration, .410"/.414" lift. The manual HO version cam is 273/289, .410"/.413" lift.

Now here is where I see a possible problem. The valve length is different, 5.026" 2 bbl intake vs 5.122" 4 bbl intake and 5.015" 2 bbl exhaust and 5.111" 4 bbl exhaust. The valve springs appear to be the same for both engines/valve lengths. However, the shorter valves can produce coil bind in some high lift cams. You probably won't have to worry as you won't be going too big. And if you do go bigger cam, then you may need to go with new valve springs as bigger lift needs heavier pressures. Your heads also have pressed in studs which can be a problem on higher lift cams -that's why Pontiac went to screw in studs.

The "066" 350 HO automatic cam listed above should work for you. 273/282 duration, .406"/.406" lift. A little bigger overall and should be OK with your valve springs. Now you can contact any Pontiac engine builder or cam manufacturer and they too can provide a great cam choice by giving them all your engine info. With 9.2 compression, stay away from any cam having a 110 LSA (Lobe Separation Angle) as these work best with 8.0 - 8.5 compressions (my opinion). With 9.2 you make have spark knock problems as the 110 LSA cams build compression pressure on lower compression engines. 112 -114 LSA is what you should stay with when choosing a cam. 

The 350 does make a good HP street engine but you build it a little different than a 400 or 455 as you can take advantage of higher RPM's. I had a 350 in a '67 Firebird that the previous owner did some head work and had a Q-jet. It was a mover and fried tires all day long. 

Now your heads can be upgraded to larger intake valves, taller valves, screw in rocker studs, port/polish etc.. But you would do this if you wanted bigger HP numbers and added matching pieces in the engine. So if your car runs good and you don't plan on a rebuild, just do the trans upgrade, duals, and a little better cam. 3.55 gearing would provide more get-up and go, but drop fuel mileage, but another way to get more performance through acceleration.:thumbsup:


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## geeteeohguy (Feb 2, 2008)

A little late to the party, but I just realized you were running a 2 speed auto trans. The cheapest, easiest way to improve the performance of your car is to simply bolt in a TH350 3 speed automatic trans. The 2 speed ST300 you have has a first gear of 1.76:1, and a final drive of 1:1. Simply installing a TH350, which has gear ratios of approx 2.75:1, 1:56:1, and 1:1 will make a HUGE difference on how the car drives. It will literally feel like you picked up 100 horsepower. And your fuel mileage will increase, too. This is a cheap, simple, bolt-on operation. BTDT more than once, and it's the FIRST thing I'd do to improve the performance of any 2 speed A-body. You can even take it further and bolt up a more expensive overdrive automatic, like a 200R4, and have even better acceleration and an overdrive to boot.


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## Thurber73 (Mar 7, 2013)

Thanks for the great info, I currently have stock exhaust manifolds but 2 1/2" pipe running all the way back with no X pipe and running thru a set of flowmasters. I have been looking into going the TH400 route for a while because it uses the same kickdown solenoid and therefore I wont have to mess with cables, linkage or brackets for the passing gear. I will definitely check into the cam I appreciate it. My water pump let go a week ago so I am getting a higher volume pump for it and probably changing the timing set as long as I am already in there that far, most likely its the original.


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> Thanks for the great info, I currently have stock exhaust manifolds but 2 1/2" pipe running all the way back with no X pipe and running thru a set of flowmasters. I have been looking into going the TH400 route for a while because it uses the same kickdown solenoid and therefore I wont have to mess with cables, linkage or brackets for the passing gear. I will definitely check into the cam I appreciate it. My water pump let go a week ago so I am getting a higher volume pump for it and probably changing the timing set as long as I am already in there that far, most likely its the original.


OK on the dual exhausts. The "X" crossover pipe is supposed to improve flow, thus a little more power. But your good with duals.

I'm with geeteeohguy on the trans. I thought you were trying to keep the 2speed. You don't need the TH-400 with your 350CI. The TH-400 is bigger and uses more HP to turn. If you plan to build your engine big, or go with a 400 0r 455 at some point, then yes, TH-400. If you can afford it, a modern 4speed automatic OD is even better. 

Food for thought -Jeg's offers a TH-350 out the door for $824 (plus shipping) and does not need the throttle cables, so not sure if that means it is a manual shift. You can probably do better to pick up a used one for cheap, get a quality rebuild kit and valve body shift kit (I like TransGo) and have your local trans shop rebuild it for you. You also want a new torque converter to go with it.

On the water pump, make sure you get the correct one for your year. '68 has the 8 bolt pump while 69' and up has 11 bolts. Also get a new water pump plate and water pump sleeves. 

Are you using an open element air cleaner? Another performance improver.:thumbsup:


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## Thurber73 (Mar 7, 2013)

Yep open element air cleaner, but my water pump is 11 bolt. With the cam specs you provided me above (The 4bbl automatic HO version is 273/282 duration, .410"/.414" lift and 112-114 LSA) when I am looking I see both advertised duration and duration at .050, which should I apply your numbers to? Pls excuse my lack of knowledge.


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## Thurber73 (Mar 7, 2013)

This is the closest I found so far...

Howards, Hydraulic Flat Tappet Camshaft, Pontiac V8 265-455
Pontiac V8 265-455 1955-1981
Advertised Duration: 273/282
Duration @ .050": 198/207
Valve Lift w/1.50 Rockers: .405/.410
Lobe Separation Angle: 111
Intake Centerline: 106
Valve Lash: Hyd./Hyd.
1600-5000. Near duplicate of the Pontiac 325HP/389 cam (GM #9779066).
Check for Availability


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## torrid red sap (Sep 27, 2014)

Back in my days of tuning big block ponchos , I ran holleys, performers, carters, and eventually ended up with factory quadrajet carbs these seem to perform best on Pontiac engines, especially lightly modded ones.


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## BearGFR (Aug 25, 2008)

torrid red sap said:


> Back in my days of tuning big block ponchos...


Umm.... er.... never seen one of those. Must be pretty rare... 

:leaving:


Bear


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## PontiacJim (Dec 29, 2012)

BearGFR said:


> Umm.... er.... never seen one of those. Must be pretty rare...
> 
> :leaving:
> 
> ...


How come I *KNEW* you were going to catch that one?:lol:


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> This is the closest I found so far...
> 
> Howards, Hydraulic Flat Tappet Camshaft, Pontiac V8 265-455
> Pontiac V8 265-455 1955-1981
> ...


OK on the open element air cleaner.:thumbsup:

The cam manufacturers use total advertised duration and duration at .050" -which is always less. The Howards cam spec has a little more lift on the exhaust -which is good. I did a check on the "066" cam and indeed it is 111 LSA. So the Howards cam would be right.

A few more things to do:

Have you played around with the secondary opening of your Q-jet? There is an allen screw that holds the small adjusting screw that will tighten or loosen the secondary air flap. Sometimes this can be a little too tight which causes the secondaries to open late. Too loose and it opens to soon and you get a bog or stumble. This is also something you can tune on your carb just to dial in the secondary opening.

There is a choke lock out found on the secondary air valve. It can keep the air valve from opening. It is held on by a roll pin. Did you remove this from your Q-jet? This is one of the things I always remove just to prevent problems if it sticks/applies at the wrong time -like when you stomp on it.

There is also another secondary lock out at the throttle shaft. It is a small pin. This can be modified to make sure your secondaries open up when you stomp on it.


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## Thurber73 (Mar 7, 2013)

No I have not done anything with adjusting the opening of the secondaries with an adjusting screw but I did drill out and install throttle shaft bushings and bending of the linkage to ensure the secondaries reach full open(90 deg.) when the primary throttle shaft linkage meets the base plate per my Cliff Ruggles book everyone here said to get. 

Also I made a mistake my water pump is the 8 bolt not the 11 bolt. I have not begun to take the pump off yet and I see in the catalogs that the 1968 timing cover has only one hole inside the water pump section and the 1969 and later models have two holes for sleeves/seals (housing pipes)...and there are no pipes/seals listed for 1968 so what is the one hole for?


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## Thurber73 (Mar 7, 2013)

Just noticed Bear's post...saw this video and found it fitting.
https://www.youtube.com/watch?v=G92qPfQ4GXo

Uuughhh :banghead:

Jon


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## PontiacJim (Dec 29, 2012)

Thurber73 said:


> No I have not done anything with adjusting the opening of the secondaries with an adjusting screw but I did drill out and install throttle shaft bushings and bending of the linkage to ensure the secondaries reach full open(90 deg.) when the primary throttle shaft linkage meets the base plate per my Cliff Ruggles book everyone here said to get.
> 
> Also I made a mistake my water pump is the 8 bolt not the 11 bolt. I have not begun to take the pump off yet and I see in the catalogs that the 1968 timing cover has only one hole inside the water pump section and the 1969 and later models have two holes for sleeves/seals (housing pipes)...and there are no pipes/seals listed for 1968 so what is the one hole for?


OK on the secondaries opening 90 deg. Play around with the secondary opening rate. Very simple adjustment, and you get to flog your car a bit when doing the adjustments -the cops will understand.:lol: I assume Ruggles book shows this adjustment. If not, let me know and I'll post a pick. Same thing with the choke lock out. When your secondaries pop open, you should get a "deep" tone that is a signature of the Q-jet. 

1968 water pump is indeed 8 bolt. Check out this Youtube video for the 1968 Pontiac water pump installation. 





Looks like the '68 water pump does not have the housing pipes. I thought they did -my error. Must be part of the '69 and up 11 bolt redesign. Pay attention to the divider plate clearance in the video. There is also another YouTube video showing this adjustment as you want the divider plate close to the impellers, but not touching. Too much gap can cause a hot engine.


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## Thurber73 (Mar 7, 2013)

Thanks for the video, I had already found the one on the divider plate clearance and watched the other day. I just wasn't sure about the housing pipes. As for the secondary adjustment my book has you adjusting the choke pull off by opening up the restriction in the vacuum supply tube of the pull off anywhere from .016-.022". I don't see anything about the adjusting screw you refer to ...but I may be missing it in the book. Your pic would be appreciated. 
Thanks Jon


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## PontiacJim (Dec 29, 2012)

Added 2 pics. The pic having 2 photos shows the secondary lock-out. It is located on top of the carb adjacent to the secondary air valve. Should be able to see it fairly easy on your carb IF it has not already been removed. A roll pin holds it on. Simply knock the roll pin out with a punch of correct size, if you have one, or something similar. You want whatever you use to knock it out to be large enough so as it does not go into the center of the roll pin and expand it. In the photo you can see the roll pin has a slot in it the full length. You want to knock it out with light blows from a hammer, don't need to kill it.

The secondary air valve adjustment screw can be seen in the other photo. It is on the passenger side. You can see the rod that goes to (I believe) the dashpot/vacuum diaphram. The allen screw is very small and in up underneath where you see that tiny screw slot. May take a little wiggling to get the allen wrench into the screw, but it is there. Loosen the allen screw while you insert a small screw driver into the adjusting screw. You know you have loosened the allen screw enough when you can turn the screw. The screw actually winds/loosens up a small spring. That small spring is what applies the tension on the secondary air valve. Too loose it pops open too soon and your engine stumbles/hesitates. Too tight and it does not open soon enough to give you a good kick in the pants -and you loose power. So your testing has to be done under wide open acceleration where you can feel/hear the secondaries open up. Once you hear them open, at that point you are done testing and can make your adjustments as needed. Repeat as necessary. It is probably best to do your tests at a speed where you can make the transmission downshift, ie passing someone. You can also do a few tests from a dead stop and floor the gas pedal.

MAKE SURE THESE TESTS ARE DONE WITH AIR CLEANER ON! If the secondary valve is too loose and opens to quickly, it can gulp in a big swallow of air before the gas catches up and this is where you get your stumble/hesitation or possibly the carb will "pop" or worst case scenario -even backfire through the carb. You don't want to start any fires under the hood. The air cleaner contains it should it happen, but a backfire rarely happens and is not typical, but just in case. BTW. You do have a small fire extinguisher on hand and a battery disconnect on your battery? These can both be lifesaver of your car should you ever have a fire develop under the hood or an electrical wire decide to fry under your dash. The battery disconnect may be the ONLY way to stop an electrical short/fire/melt down. Talking experience here. Cheap insurance. 

OK, the adjustment. You should be able to move the screw left (loosen as I recall) and right (tighten). I loosen the spring tension where the secondary air valve is laying flat. Turn it to the right to tighten the spring just until you see the secondary air valve open. This is too much spring tension, so back it off until the valve lays flat again. Then just lightly snug the allen screw because you will be adjusting it during your testing. I generally loosen the screw/spring tension until it does stumble/hesitates when you slap the pedal to the floor and your secondaries open up, ie passing gear/accelerating from a dead stop. From that point, I then begin to apply more screw/spring tension. Do not over tighten the allen screw -use common sense here, just snug it up again. You don't need much adjustment on the screw to make a big difference. You can turn the screw about 1/8" at a time, or turn it 1/4" at a time until the secondary air valve opens without a stumble/hesitation from your engine during wide open acceleration. Then loosen it back 1/8" of a turn to see if you got it right or if you can go the 1/8" turn setting. If the engine stumbles, then tighten it back the 1/8" turn and now tighten the allen screw for its final time -your done. 

If while driving it, you find the carb stumbles when you open the carb wide open, you can simply tighten the screw/spring another 1/8" and see if that does it. Repeat if necessary. 

I used to loosen the allen screw just enough to keep a "tightness" on the adjusting screw so that I could tighten or loosen the screw, but it would not back off or slip. Makes for easier roadside adjustments. Once I got air valve adjustment right, then I would simply tighten the allen screw and I was done.

This may all sound scary or complicated, but it is fairly simple and easy to do once you give it a try. I tried to explain myself as complete as possible and sometimes that comes out like the adjustment will be complicated or something you don't think you can handle. This gives you more insight into your car and its functions and THIS is what makes owning a Pontiac what it's all about.:thumbsup:


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