# new intake manifold and carb for my engine



## Chris-Austria (Dec 23, 2010)

Hi!

I'm thinking of a new manifold and carb instead of the tri-power. If we cannot fix it, I don't want to wait forever until someone can rebuild my tri-power. 

The question is, if my mechanic cannot repair it, which combination would be good for my new engine. I have now a 435cui with E-heads, headers, msd distributor, raiv4 cam... So I guess the 1500-6500 rpm performer dual plane intake manifold is the best choice. Carbs are 650 or 800cfm and I guess the 800cfm would be best. What do you think?

I want good power at low rpms and really good power at mid and high rpms. Nice throttle response and not the worst fuel economy would be nice too. But I don't want to lose power because of less fuel economy... dosn't matter that much.. best power and throttle response are most important.

Thank you!
Chris


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## Chris-Austria (Dec 23, 2010)

What I also need to know.. do I need new parts to connect the throttle (gas pedal) to the new carb or will the old one from my tri-power fit? Don't have any experience with that


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## ALKYGTO (Mar 29, 2010)

I'm gonna say Performer RPM (since you have the E heads) and a 750 Holley. Good all around set up and if you switch back it will be easy to resell if you want to. :cheers


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## ALKYGTO (Mar 29, 2010)

Chris-Austria said:


> What I also need to know.. do I need new parts to connect the throttle (gas pedal) to the new carb or will the old one from my tri-power fit? Don't have any experience with that


Honestly you'll just have to have it all on there to see. The RPM is gonna be taller than the trips ( Have to look for hood clearance too!) so that might make up the difference. Lokar makes some nice adjustable cables that you can use also. Summit has em.


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## BearGFR (Aug 25, 2008)

You've got several options. If you want to avoid the chance of hood clearance problems, then you'll want to go with a manifold that was supposed to be a direct replacement for factory manifolds (or some version of a factory manifold). Something in my head just tripped... are you SURE your tripower manifold is completely covering the intake ports in the heads? I was running a port-matched factory iron intake with my Ram Air IV's and it fit, but just barely. When I put on the ported E-heads, there was no way. The factory intake didn't come close to covering the ports on the new heads so I had to use a different manifold. I wound up using an old Edelbrock Torker-I because it's what I had available, it's a direct replacement for the factory manifold (all the accessories and even the ram air system still line up correctly), and it was tall enough to cover the ports on the new heads.

Anyway, other options for you would be a reproduction factory aluminum Ram Air IV manifold or a Torker-1 (both of those accept spread bore QJet carbs). I think the Edelbrock performer (not the RPM) might also be a direct replacement but I'm not sure.

In terms of performance though, on your engine, none of the aftermarket manifolds are going to run quite as well as the factory ones if they've been set up correctly.

Bear


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## Chris-Austria (Dec 23, 2010)

I didn't ask the engine builder if the intake manifold fits the heads perfect. His job was to make it fit and I hope he did  I'll contact him! 
I now have the stock tri-power manifold and the rather high tri power carbs. The ram air pan and seal is about 2" high and it touches the hood like it is supposed to. 

I didn't think that the Edelbrock intake may run worse than my old tri-power intake. If I chose the performer intake (idle-5500rpm) do you think this would also match my needs with the engine's camshaft?

Holley sells lots of different types of carbs, I don't have a clue which one to chose. The Edelbrock Thunder AVS looks nice to me, but I have no experience. Why should I chose a Holley instead of the Edelbrock?


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## BearGFR (Aug 25, 2008)

Chris-Austria said:


> Why should I chose a Holley instead of the Edelbrock?


Oh my, that question has started wars and toppled governments... 

(Seriously, the "best carb" question tends to generate lots of "passion"...)

I'll do my best to be "objective"...

Advantages of Holley:
They're siimple.
They're plentiful.
Lot's of people know about them.
You can get them pretty much as "big" as you'd ever want.
Parts are 'everywhere'.
Disadvantages of Holley:
They're simple (they don't have a dedicated part-throttle cruise circuit so they tend to not get mileage as good as a more finely "tunable" carb.)
Some of them like to "eat" power valves if the engine ever backfires.

Advantages of QJet:
Precise metering (they do have a dedicated cruise circuit) so they'll give better mileage than other brands of comparable capacity.
Variable CFM - they'll pass only as much air as the engine can handle, up to their limit.
Disadvantages of QJet:
Not as simple.
Once plentiful, but good, un-trifled with examples are getting harder to find.
Upper CFM capacity of 800 CFM (some models), others are 750 CFM - may not be enough for a large displacement/high rpm engine.
Not as many people know how to properly set one up (although many people "think" they do, which contributes to good carbs being effectively destroyed).
Parts sources are drying up.

I've got no direct experience with Edelbrock carbs, but I've "heard" from others that they're hard to get set up and don't run as well as a QJet.

I'm running an 800 CFM QJet on my car and I like it a lot.

Bear


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## ALKYGTO (Mar 29, 2010)

BearGFR said:


> Something in my head just tripped...
> 
> Bear


 You are truly a child of the 60's Bear. :seeya


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## Chris-Austria (Dec 23, 2010)

I found a thread "Performer or Performer rpm" manifold.. and now I start to think the Performer is better for my needs as I dont want to lose low rpm power and 5500 is about my max rpm (I think 5500-6000 will be the Limit for my combination)

A rebuild qjet would need an adapter I guess? Its just that its very simple to get a nice Holley or Edelbrock and hard to get a good qjet for me 
I thought of the Edelbrock Thunder AVS 800 endurashine with electric choke.. not a good deal? Which Holley should I look at?


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## kilkm68 (May 5, 2011)

I have an Edelbrock 800 cfm thunder series with electric choke and the performer manifold on my 474 and I like it a lot. For a street car I think they are hard to beat. The car starts on the first click of the starter, idles nice, is very responsive and gets good gas mileage (16-18 mpg if I keep my foot out of it.) It took a little experimenting with jets and metering rods to get best performance with this engine, but they are simple to change. I replaced a 750 cfm Demon double pumper that was previously on the car. The motor did have more power with the Demon but used a tremendous amount of gasoline. I'll probably get a Holly for it if I race it this summer, but for a street carb I like the Edelbrock.


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## BearGFR (Aug 25, 2008)

ALKYGTO said:


> You are truly a child of the 60's Bear. :seeya


Thank you for the compliment 

:cheers

Bear


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## Chris-Austria (Dec 23, 2010)

This gas milage sounds pretty good, would be nice but I can surely tolerate to burn more fuel if it gives more power 

Lets say if I try to use all parts from Edelbrock... is 650 or 800cfm better? I guess 650cfm is not big enough... and will the performer manifold provide better low end torque than the performer rpm? I won't get over the 5500rpm very often and if I do, will the performer manifold be much worse than the performer rpm at my max. of 6000rpm?


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## Chris-Austria (Dec 23, 2010)

What do you think of this carb? Holley Performance Products 770 CFM Ultra Street Avenger Four Barrel Carburetor - Blue™  0-86770BL
Will it fit the Edelbrock intake manifold? (performer or performer rpm)


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## BearGFR (Aug 25, 2008)

770 CFM is going to be marginal on your engine, in my opinion. I think it'll be happier with something around 850 (or so). As far as fitting, generally there are two kinds of carb bases: spread-bore where the front barrels are small and rear ones large (like the QJet), and square-bore where all 4 are the same size. Within those two families, they pretty much all have the same dimensions (except for the giant Holley "Dominator" series.)

I wouldn't give up on the tri-power just yet though. Now that you know it's very lean at idle, now you've just got to figure out how to convince it to pass more fuel through the idle circuits. I did a quick Google search and found this link:
Services | Pontiac Tripower

Notice the part where he says:
"I modify the carbs to your needs. For example, if you are running a 455 and using a tripower that started life on a 389, the idle circuits need to be opened up, and jets need changed. With a radical cam, the power piston may need modification."

Sound to me like that's almost exactly your problem.

The good news is, this is a problem that other people have seen and it has been solved before. All that remains is figuring out what to do about it.

The same site has a DVD that might just have the information you need:
DVD Tripower Basics, Mods, and Troubleshooting | Pontiac Tripower

There's also a discussion with information here:
Pontiac Street Performance - Tripower with KRE heads: Electric choke???

Keep cool, it's just an engine - all it needs is a proper volume of air and fuel in the correct proportions. 

Bear


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## Joe'sToy (Mar 9, 2012)

Agree with Bear about this site. I got his DVD for my Tr-power set-up, as I was not very knowledgeable when it came to Tri-power carbs. I also got his phelonic spacers for my Tri-power and it cured some problems that I was having.

The owner of PontiacTri-power.com is very keen and friendly to deal with. He really knows Tri-power set-ups. I would think for the price of a long distance call or email, you could get some good answers.


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## Chris-Austria (Dec 23, 2010)

I have some new questions 

1. What do you think of the Holley Ultra Double Pumper and the Holley Ultra Street Avenger? The difference isn't big.. one has mechanical secondaries and the other vacuum secondaries and I was told the mechanical version is the better choice for my engine (but will need more fuel.. I don't care about that).

2. I want either the Performer or the Performer RPM intake. If I choose the std Performer and use a spacer (0.5-1") I can make sure not to run into clearence issues and if I watch the simulation of my engine my max hp is at 5550rpm, what would fit into the power range of the std Performer. Probably the Performer RPM will give more power at mid range but I'm pretty sure it will lose some power down in the rpm range because it has bigger intake runners. On the other hand if I now try the std. Performer and feel that there should be more power at mid-high rpm's I can change to a Performer RPM later and keep the carb. I'll see if my driving style changes now with the rebuild engine plus if I first use the std. Performer I can check the clearance very easy to make sure the Performer RPM would fit if I decide to change..

3. Are you sure 770cfm is marginal if I don't rev the engine up to more than 5600-5700rpm? The Holley calculator says 750-800cfm depending on the secondaries type and what they have available with electric choke.

4. What is the rpm range of the tri-power? Because I think it doesn't look like a high rise manifold. Is it taller than the std. Performer or has bigger intake runners?

5. I decided to put the tri-power into storage for now.. I know many things now that might get it to work with my engine, but I cannot find someone who will adjust it to my needs. They are afraid of it and have no experience, so if I spend even more money for the tri-power and something won't work like in theory it might be damaged and I don't want to risk that. The rebuilded carbs would need another rebuild and testing, working, adjusting... would cost me more than a new intake and carb. The mechanic who will do the job told me he has very good experience with the Holley Double Pumper and has build some Pontiac engines with such carbs with very good results. I really like the tri-power but I need to get something that the mechanics here can adjust and are familiar with.. the best system won't help me if nobody can adjust it


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## Chris-Austria (Dec 23, 2010)

Hey  I'm back with some pic's of my new Setup.. the Tri-Power was removed and is waiting for a proper rebuild. Until then I got following parts:

- Edelbrock Performer manifold (RPM would not fit under my hood, maybe if I used a pretty small filter)
- Holley Double Pumper 750cfm with electric choke

It runs great now!!! Couldn't drive it more than an hour because it's snowing now 
I probably will use another thermostat housing and radiator hose soon, also the fuel pressure is pretty low with 4-5psi. Or do you think thats okay? Had to cut the fuel lines because they wouldn't fit.. but I'll build some nice fuel lines by my own soon.

Here are the pics:




























The tri-power surely is more desireable but for now I'm really happy with the setup and in the future I'll switch to the tri-power again to see the difference. I'm curious how much it will cost me to send the carbs to the US, have them rebuild and get them back.. but I don't see another chance to get them to work like they should do.


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## kilkm68 (May 5, 2011)

Looks great. I like that carb considering one myself. Snowing here too, not very good GTO weather!


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## ALKYGTO (Mar 29, 2010)

Glad to see you got your GTO up and running Chris!

We have snow here too, 13.5 inches yesterday, definitely not GTO weather.

Pics of your engine look great, very organized looking engine bay. Just get rid of that rubber line as soon as you can :willy: I know you said it was temporary. :cheers


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## BearGFR (Aug 25, 2008)

Looks nice, Chris. Like Alky said, please DO replace that rubber line asap. I'd hate for you to have to stand and watch that pretty thing burn to the ground...
 

5 psi _might_ be a little on the low side, but the real test will come when you have an opportunity to really run the car hard through all the gears. If there's not enough fuel to keep it fed, it'll be pretty obvious.  I wouldn't fiddle with it until you know for sure it needs fiddling.

Bear


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## Chris-Austria (Dec 23, 2010)

Do you think the rubber lines are that dangerous? I don't like the look of them and also I believe that metal lines are the way to go.. do you know a quality set that will fit with the Edelbrock manifold? If it's just "plug&play" I'll get one today at Summit!

I read that the carb wants up to 7.5psi of fuel pressure. There are pumps that give about 7psi... How do I know if I need a pressure regulator? Or is this just something that is needed with high pressure pumps such as 10psi or more?


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## ALKYGTO (Mar 29, 2010)

Here are some selections from Summit Racing, Speedway Performance and dont forget to check out Bo Laws (although I'm not a fan of pink... I do run their belt drive pump which is awsome and feeds up to 2500 HP). :cheers

http://www.summitracing.com/parts/hly-12-840

http://www.summitracing.com/parts/rpu-3000

Adjustable Fuel Log for 4150 Holley Style Carbs - Speedway Motors, America's Oldest Speed Shop

Fuel Log : BLP Racing Products LLC, Racing engine parts Holley carburators gaskets belt driven fuel pumps

Honestly your carb can handle only about 6-7 psi at idle so that is where you are stuck with pressure. A big motor can actually drain the fuel bowls if the pump can't keep up hence why some guys run larger bowls and or extensions.

I don't think you'll be in that boat but I always recommend running the large #8 fittings to the carb as opposed to the #6 and the fuel log can act as a "mini tank" to hold that much more fuel to prevent starvation. I like the idea also of mounting the regulator as close to the carb as possible. Also consider a return line setup, some regulators have them some don't. I like bypass regulators, you always have a fresh fuel supply to the carb and the fuel stays cooler.

The setup I like the best for your car is the one from summit with the regulator in the middle and the #8 hardlines to the bowls. Probably plenty for your car and not too expensive. The logs are very nice too in that they hold more fuel and are "adjustable" for length, at least the one from Bo Laws that I saw, but again maybe ask if they are available in another color .

John


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## Chris-Austria (Dec 23, 2010)

Thank you for the selection! The Summit parts look nice and I think they could fit. The others will not fit because of clearance issues.
The problem is that I need a rather long line into the carb because otherwise it will not clear the electric choke, but a straight line will touch the manifold. So I need something that is long but makes a 45° turn.

I'd like it the most to build a custom line.. but cannot find the parts I need (because I don't know what will work and what can be connected). 

If you look at this (I know.. could be the painting of a 5 year old child): http://sphotos-d.ak.fbcdn.net/hphotos-ak-ash4/3631_2982626582043_875122533_n.jpg

The red lines need to be about 5" long, the blue line needs to fit both red lines (9,25" I guess) and lead to the front of the engine where I want to mount my fuel pressure gauge and from there I probably can run the rubber line to the fuel pump.
Is there a chance to build something like this with parts only in chrome or blue with chrome?

If not I could test the Summit parts you showed me and hope they fit.. but something has to be done... Maybe the other parts would fit if I use a carb spacer (1")... otherwise they will surely hit the manifold like the one I used and had to cut (http://www.summitracing.com/parts/sum-g3120-2)


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## Chris-Austria (Dec 23, 2010)

What tubing size should I use if I build it by my own? 3/8" or 1/2"? Adapters will be -6AN or -8AN. I think 3/8" or -6AN will be good because it looks like the Holley fuel lines have the same size, but should I "upgrade" to -8An or 1/2"?

edit:
I think I'll take the -6AN and 3/8" tubes and I also made a painting. Can you please tell me if it will work this way? Or if I could build it better/easier?


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## leeklm (Mar 11, 2012)

looks nice chris. One thing to watch out for when it gets hot out... I had an issue with my previous Holley after the car was shut down on a moderate hot day, the fuel would "boil" in the bowls due to the engine heat. This created a condition where the car would stall and not run well. Kind of felt like vapor lock. 

Summit sells a shield that bolts on beneath your carb, and is supposed to delfect the direct engine heat away from the bowls. I switched over to a qjet so never did try the shield to see if it helped.


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## Chris-Austria (Dec 23, 2010)

Thanks for the Information. I'll wait until summer and if I have the same problem I'll try the shield! But my manifold and heads are Aluminium, maybe there isn't that much heat after I switch it off.. we'll see 

Another question.. to connect the fuel lines to the 6AN adapters.. what's the best way to do it?

1. http://www.summitracing.com/parts/sum-2200075n
2. http://www.summitracing.com/parts/rus-639203
3. http://www.summitracing.com/parts/sum-220633-2n and http://www.summitracing.com/parts/sum-220634-2n

The question is:
Are #1 and #2 the same? An adapter to connect the Aluminium line without flaring? Sounds pretty nice if it works!
And the second way to connect the fuel lines would be to use nuts and sleeves I guess? Will the parts from #3 work to connect the 3/8" fuel line? I guess I would have to flare the end of the fuel line if I used the nuts and sleeves.

What do you say?


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## BearGFR (Aug 25, 2008)

Chris-Austria said:


> Thanks for the Information. I'll wait until summer and if I have the same problem I'll try the shield! But my manifold and heads are Aluminium, maybe there isn't that much heat after I switch it off.. we'll see
> 
> Another question.. to connect the fuel lines to the 6AN adapters.. what's the best way to do it?
> 
> ...


Hi Chris,
I didn't jump in sooner because I wasn't sure if you were talking about the line from the tank to the pump, or just immediately prior to the carb.

Anyway, to answer a couple of your questions. No #1 and #2 aren't the same - but they're close. Both connect to 3/8" hard line (steel or aluminum) but where they differ is that the other side of #1 connects to "bare" braded AN-6 hose, where #2 connects to a male fitting that has been attached to AN-6 braded hose. Close, but not identical.

3/8" line going straight into the fuel bowls is ok because that run tends to be very short and you're actually splitting the fuel feed into two parallel feeds, each going to "half" of the carb. The line from the tank to the pump (if you still have an engine driven mechanical pump) is a different story. The factory 3/8" line was ok for stock engines and maybe even mildly modified ones, but once you start making significantly more than factory power levels it fairly quickly becomes not big enough to keep up with demand. I'm running 1/2" hard line all the way from the tank, through the pump, to the regulator input on my car, for example.

Which fuel pump are you using?

If it's the factory style pump it probably is designed to connect to 3/8" flexible hose on both input and output and that'll be hard to change without changing to a different pump. So the next best thing would be to keep those bits of hose as short as possible. Just like there's a very short run of hose that connects from the steel fuel line coming out of the frame to the input side of the pump, what I'd do would be to use another short piece of hose (3 to 4 inches, tops) to connect to a hose barb fitting on a length of braided hose to continue up to the "top" of the motor. Something like this:
http://www.summitracing.com/parts/sum-220712
Use a very short piece of "rubber" 3/8" fuel line to go from the pump output to the red part of this fitting.
Then coming out of the blue side of that fitting, use a length of AN-6 braided hose coming up the front drivers side of the engine (behind the brackets next to the head). The hose will have a male fitting on the lower end to connect to the hose barb fitting, like one of these:
http://www.summitracing.com/parts/ear-840106erl/overview/
(The blue end connects to the hose barb fitting, the red end connects to the hose)
Please DO support that run of braided hose with some sort of bracket and don't just leave it hanging. You want to keep it from moving around because that will constantly cause that short piece of "rubber" hose coming out of the pump to be flexing, leading to leaks...

Going into the carb, you've got options. I do recommend NOT using aluminum because the engine vibration will tend to "work harden" it making it brittle and prone to cracking - which is a bad thing for fuel lines. I'd use hard steel tubing, or at least stainless braided hose. If you use something like this:
http://www.summitracing.com/parts/sum-g3120-2
It's nice because it also has a fuel pressure gauge right where you want one.
If you do use something like that, then you'll need one of these:
http://www.summitracing.com/parts/sum-220648
to thread into the hard line and a fitting something like this:
http://www.summitracing.com/parts/sum-220690
on the end of the braided hose to connect to it.

If you later install a fuel pressure regulator (which you will need to do if you "upgrade" to a fuel pump that supplies higher pressure), then the place to install the regulator would be "between" that hard line going into the carb and the braided hose coming out of the fuel pump. The guage will already be right where you need it.

Make sense?

If you got all those parts I listed, then all you'd need to complete the connections would be a length of -6AN braided hose long enough to run from the output of the pump to the input side of the hard tubing going into the carb. Cutting that stuff and installing the hose ends can be tricky (and painful). The trick to it is to wrap the hose tightly with several rounds of electrical tape, then use a hacksaw to cut through the center of the tape, being careful to make your cut "square" with the long axis of the hose. That helps keep the braid from fraying and poking lots of holes in your fingers while you're trying to attach the hose end fittings. (remove the tape before attaching the hose end).

Bear


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## Chris-Austria (Dec 23, 2010)

Hi!

Thanks a lot for the Information.
I already have ordered some Aluminium lines.. but I can change to stainless steel. The http://www.summitracing.com/parts/sum-g3120-2 is what I tried before. It doesn't fit and I had to cut it. 

I'll now build the fuel line for the carb inlet first and connect it to the old fuel pump with the old 3/8" hose. The Tri-Power also had alum. lines and they seem to be in good condition after all these years.. but going with stainless shouldn't be much trouble if the flaring tool can handle it 

I'll use following parts:

1. 7/8" to 6AN male for the carb http://www.summitracing.com/parts/rus-640221
2. nuts and sleeves 6AN to connect the fuel line http://www.summitracing.com/parts/rus-660571 and http://www.summitracing.com/parts/rus-660651
3. Tee Fitting 6AN to connect the dual inlet lines http://www.summitracing.com/parts/rus-661021
4. 6AN male to 6AN male with 1/8npt for the pressure gauge http://www.summitracing.com/parts/rus-670001
5. 6An to 6AN hose to connect the fuel hose to the pump (this will go into the Tee-Fitting) http://www.summitracing.com/parts/rus-610021

Do you think this will work?

I have the stock fuel pump that I may change later if needed and build the lines like you said. First I want to test drive the car and see what is needed. The fuel line for the carb inlets will be 3/8" (6AN).


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