# 69 350 now falling on its face



## Boomstick (Sep 13, 2021)

So i got my 69 back from the shop on the 18th after having them do the rear main and putting the flowtech headers on. It cost way more than i budgeted due to unforeseen issues so currently i only have open headers with just 2.5" collectors. Before the headers, with factory exhaust and stock style mufflers, the car would spin about 1/4 the way through first from a dead stop at idle by just stomping on the pedal and pull pretty nicely all the way to second gear, then pull well on into 3rd. Now it will burn all the way through first, shift into second, pull like the dickens halfway through second and fall flat on its face up until 3rd, then pull again and flat on its face... I'd say it feels like it lost half the power on the top end... The only thing that changed is the exhaust. Currently since i have an hei, the hood tach doesnt work so my guess is it's dropping off around 4000 to 4500. I've farted around with the timing, the carb and even tried non ethanol fuel and all i can manage to do is make it miss and idle rough or run worse. I did put a new air cleaner on that hit the hood so i put a 1/2 plastic spacer in and took out the 1" aluminum spacer i had originally, but i swapped all that back to the old stuff and nothing changed so im sure the new air cleaner and spacer have nothing to do with this. Its almost like its loading up on the top end but it isn't blowing black smoke nor does it smell likes its loaded up, plus its only a 600 carb so there's that...

Timing is set at 6deg at idle with the advance disconnected. The vac adv is hooked to manifold vac normally, switching it between port and manifold changes nothing but the idle. my 1970's sears timing light does not have the advance knob so i don't know where its timed with the vac adv hooked up but iirc its in the same place it was before the headers... all adjusting the timing does is make it worse...

XS code 69 350, stock cam (i think), 1971 #94 heads, edelbrock rpm intake, 600 summit carb, pertronics flamethrower hei. stock TH400, 3:23 safety-trac rear.

I'm thinking maybe I need more carb now? My fiance suggests maybe since it has sooo much more bottom end, the top just feels pathetic now...

Thoughts?


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## An0maly_76 (Dec 25, 2021)

Sounds like a fuel issue, but opposite of what you're thinking -- not enough. Engines need more fuel at higher RPM, and won't be happy if they don't get it.

Check the simple stuff first. Could be a dirty fuel filter. I had one that gave the engine vapor-lock after a few miles. Cost me a $600 tow bill because I didn't think of a $2 filter. Carb could also need cleaning, dirty jets maybe. If that's not the problem...

My old man's '69 Judge had a similar issue after an engine rebuild (car had sat for years and he didn't think about rebuilding the carb also), but in all gears. Almost the moment the secondaries opened, the engine would bog and fall on its face. Culprit turned out to be a pinhole in the fuel bowl float that had flooded it with fuel, keeping it at the bottom of the bowl. This prevented accumulation of sufficient fuel for hard acceleration.

Basically, it had enough fuel until you really opened it up, then it fell flat on its face in the same manner you describe. This was on a Q-Jet, not sure if yours is also. I won't promise yours is doing the same thing, but it's a likely scenario, and certainly sounds like it. Unlike loading up, it won't blow black smoke and it won't stumble under certain conditions.

If that's what's going on, possibly the float is just starting to flood, which is why it pulls okay until higher rpm. Another possibility is the accelerator pump. In either case, it sounds like something in your fuel system needs attention. If it's carb issues, I would rebuild if it's been okay until now. One other thing -- the lift pump (mechanical arm pump that feeds the carb) could be going bad also.

Fuel issues really are simple, the engine can't burn what the carb can't give it, and the carb either gives the engine what it gets, or what it can give.

If any of this is the case, though its timing might seem interesting, don't scream at the shop, it's nothing they did, just something that happens over time. Unless they opened the carb to poke a hole in the float, and I really don't see them doing that for an exhaust job.


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## armyadarkness (Dec 7, 2020)

@Boomstick if you have a stockish 350 with a 600 cfm carb, and it's spinning a posi with 3:23's, through 1st and into 2nd, then you should be the happiest guy on Earth. My modified 400 with an 800 cfm carb, pro billet dizzy with complete timing curve, headers, and 336's won't do that.


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## An0maly_76 (Dec 25, 2021)

armyadarkness said:


> @Boomstick if you have a stockish 350 with a 600 cfm carb, and it's spinning a posi with 3:23's, through 1st and into 2nd, then you should be the happiest guy on Earth. My modified 400 with an 800 cfm carb, pro billet dizzy with complete timing curve, headers, and 336's won't do that.


No offense, but it sounds like you've got some tuning issues or perhaps a restrictive exhaust. My old man's '69 400 (also slightly modified) would burn all four gears without moving 10 feet. Of course, it had 4.33s, but it was also a posi. I just think if you have a modified 400 it shouldn't have a problem breaking loose. Carb seems a bit large TBH -- Lots of people go too big on the carb assuming bigger is better, but it is possible too big a carb can hamper performance. Just my $0.02.


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## armyadarkness (Dec 7, 2020)

Thanks for the thought and advice, but if you do a quick search, you'll see that there's not many areas of my build which havent been dissected to death here, over the last year. 3 dizzys, 2 cams, 2 carbs, 3 sets of mufflers, 2 sets of rockers, 3 coils...

The difference between 336's and 355's is significant... but 433's would be like strapping a rocket pack on tit mouse. IMO, your underestimating the advantage of such low gearing, especially with a 4 speed and shorter car.

As for the carb, I agree that with the chevy and ford crowd "over carbing" is a big issue, but it's usually the opposite with Pontiac. Most people here under carb. Anything less than a 750 on a Pontiac 400, is generally considered a move toward pure economy. That being said, I run an AFR gauge and do my own jetting, so as it sits, Im well on the lean side.

My car will burn the tires a good amount, from a stop at idle, break loose in 2nd, and chirp 3rd at 80mph, with 336's. Yet I agree with you that it seems well under powered compared to my last two Pontiac 400's. However, I think 355's or 373's with a 2800 stall would be a game changer.

I also drive my car far, "a lot", so gearing down isnt high on my list, but I am converting to a manual soon.


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## BearGFR (Aug 25, 2008)

I agree with the idea that the most likely cause is it's running out of fuel. If all your filters, including the sock on the fuel pickup inside the tank, are open and not causing a restriction, then the next suspects are the fuel pump itself not being able to keep up with demand, and/or the whole fuel line between the tank and pump needing to be of larger diameter. 

Bear


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> @Boomstick if you have a stockish 350 with a 600 cfm carb, and it's spinning a posi with 3:23's, through 1st and into 2nd, then you should be the happiest guy on Earth. My modified 400 with an 800 cfm carb, pro billet dizzy with complete timing curve, headers, and 336's won't do that.





armyadarkness said:


> @Boomstick if you have a stockish 350 with a 600 cfm carb, and it's spinning a posi with 3:23's, through 1st and into 2nd, then you should be the happiest guy on Earth. My modified 400 with an 800 cfm carb, pro billet dizzy with complete timing curve, headers, and 336's won't do that.



Sorry, I didn't mean for it to sound like it spins all the way through first, just until it shifts which is quite early, say maybe for 2 or 3 seconds at most at about 15-25mph and it doesn't spin into second but it pulls way more after it shifts. Plus it's one legging and I'm running 275 35 18 nankangs on the rear which are significantly smaller in diameter than 235/15's and are about as sticky as plastic. That's with it just in drive, I haven't tried to shift it manually yet, the shifter still needs adjustment and won't shift to second manually ratcheting it. 

Anyway, say I'm sitting at a light, it changes and I mash the pedal, it'll spin for about 2 second, shift and pull well until about 4k and it just falls flat until it decides to shift again and then pulls well until about 4k then falls flat. The more I think about it, the more I think I need to put the 750 Holley back on now.


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## armyadarkness (Dec 7, 2020)

Yeah. A 650 is for a modified Chevy 350. 

Pontiac starting point is a 750


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## Lemans guy (Oct 14, 2014)

Sounds lean to me at high RPM, secondaries and or accelerator pump cannot deliver possibly…..fuel pump as Bear noted cannot deliver adequate fuel…or as Anomaly said fuel filter crud died up…

you opened up the exhaust flow improving the flow and therefore the power…..but now the same level of fuel is not enough…..

yes put the 750 back or put a AFR meter in the tailpipe, watch it when it bogs…..bet it goes lean…..bogs…and then pulls back….

lean at speed….first look at those things…..


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## 67ventwindow (Mar 3, 2020)

My vote is lean. But I would verify with a AFR. 
Are you going to run open headers?


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## An0maly_76 (Dec 25, 2021)

army - I guess running lean is better than running rich... But how lean? I don't think it takes much either way to affect performance, especially with a larger carb like that. Also, which heads do you have? I understand there are significant flow differences across the five different Ram Air heads.


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## Boomstick (Sep 13, 2021)

67ventwindow said:


> My vote is lean. But I would verify with a AFR.
> Are you going to run open headers?





Currently plan is a set of these turned down before the axle:










HOOKER Universal bolt-on 3 Bolt 3 inch turnout style Collector Muffler Chrome | eBay


Find many great new & used options and get the best deals for HOOKER Universal bolt-on 3 Bolt 3 inch turnout style Collector Muffler Chrome at the best online prices at eBay! Free shipping for many products!



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I got them for $100 off a friend of my dad's. I'm running 2 1/2 inch collectors and pipe to them and welding another collector to the end of the mid pipe so I can take them off and leave the mid pipe if I like or I can take it all off at the header...



I'll probably never take them off, just a cool option to have IMO...



And they're chrome...


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## armyadarkness (Dec 7, 2020)

An0maly_76 said:


> army - I guess running lean is better than running rich... But how lean? I don't think it takes much either way to affect performance, especially with a larger carb like that. Also, which heads do you have? I understand there are significant flow differences across the five different Ram Air heads.


My car is on the lean side now, because of the dense winter air in Jersey. Although I do prefer to be on the lean side anyway, but most around here would recommend that I went a full point richer with my mixture. Which is why I love the Edelbrock carbs so much. I could easily swap out needles, springs, mains, and secondaries, in under 5 minutes, without draining fuel.

The heads are the original 670's.


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## An0maly_76 (Dec 25, 2021)

army - Just a thought (and this could be a good thing) perhaps your suspension is just dialed in that well? I have seen cars that just hook and go if everything is perfect.

Otherwise, I assume you're running premium. Having traveled the continental US coast-to-coast driving trucks, as well as knowing someone who lives in Washington state, I know that certain locations require different octane ratings for altitude (85 octane for example), which affects the oxygen content of the intake air. Perhaps some octane boost or racing fuel would give that extra oomph that is missing?

I wonder if this might apply to predominantly cooler / colder climates also regardless of altitude. Say, for instance, your engine might do everything expected on 93 octane at say, average temps of 70 degrees, but perhaps average temps of 50 would stifle it somewhat. Also, I found some interesting info on the 670 heads you mention. Maybe all this was already done to yours, but might be worth a read.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> My car is on the lean side now, because of the dense winter air in Jersey. Although I do prefer to be on the lean side anyway, but most around here would recommend that I went a full point richer with my mixture. Which is why I love the Edelbrock carbs so much. I could easily swap out needles, springs, mains, and secondaries, in under 5 minutes, without draining fuel.
> 
> The heads are the original 670's.


I cant decide between a 750 edelbrock or a 750 summit... i already have a 600 summit (knock off of the holley 4010) and ive been pretty happy with it on this car thus far so i might go that route... 

just like the4800 vs 4801 cam, i cant decide summit vs edelbrock...


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> I cant decide between a 750 edelbrock or a 750 summit... i already have a 600 summit (knock off of the holley 4010) and ive been pretty happy with it on this car thus far so i might go that route...
> 
> just like the4800 vs 4801 cam, i cant decide summit vs edelbrock...


Well, if you go with the Edelbrock, you'll want the AVS2, which is only available in an 800. It has dramatically improved fuel atomization, for better response, etc.

Obviously, @PontiacJim and I are going to push these, because they're very easy to tune and they just work... That being said, I don't need to tell you that aside from us, Earth will tell you to get a Holley.

One thing I will say is that in order to compare apples to apples, always include the price of fuel lines, gaskets, regulators, pumps, and jet kits... IF necessary. The Eddy carbs have unique fuel inlets, as do Holleys, and they don't like more than 6 psi of fuel pressure, so you'll either want a regulator or the Edelbrock fuel pump.

The advantage to the fuel pump is that it's a high performance, clockable, rebuildable unit, which many of us use with or without Eddy carbs, just because it's great.

And... Jets. Unless you're planning on luck, might as well get the jet kit, too.

FYI, if your heat crossover is active, Edelbrock also makes a heat insulating gasket. Which works well.


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## armyadarkness (Dec 7, 2020)




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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Well, if you go with the Edelbrock, you'll want the AVS2, which is only available in an 800. It has dramatically improved fuel atomization, for better response, etc.
> 
> Obviously, @PontiacJim and I are going to push these, because they're very easy to tune and they just work... That being said, I don't need to tell you that aside from us, Earth will tell you to get a Holley.
> 
> ...


I think you've talked me into the Edelbrock...


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## Boomstick (Sep 13, 2021)

Is the factory fuel pump going tp be ok with the 800 eddy? The 600 handles it just fine.


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## Jared (Apr 19, 2013)

Boomstick said:


> Is the factory fuel pump going tp be ok with the 800 eddy? The 600 handles it just fine.


It will probably be fine. I've run their 600 carbs on a couple cars, both with stock fuel pumps and never had a problem. I think the issue comes on high HP applications where a super high volume pump is used, with the increased flow capabilities comes higher fuel pressure. Then a regulator is needed to step down the pressure. If you look, Edelbrock sells two different pumps for the Pontiac. You would need to lower GPH pump. If your 600 ran fine using the stock pump, I can't think of any reason that the 800 wouldn't as well. That all being said, an 800 cfm carb on a 350 may be too much for it. Like others have said, your fueling issue could be further up the line and it just came to head when you installed headers and open exhaust.


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## armyadarkness (Dec 7, 2020)

Tuning Up the Edelbrock AVS2 Carb


Edelbrock has developed new parts for their AVS line of carburetors, dubbed AVS2, that drastically improve throttle response.




www.motortrend.com






Boomstick said:


> I think you've talked me into the Edelbrock...


In that case, you may be interested in these Superbowl Elevator Passes.

Seriously though, I never try to talk anyone into anything, I merely try to enlighten them to more options. Not sure how these carbs got such a bad reputation. The most sought after muscle cars ever made came with these carbs on them.

Im also not sure where the idea that they're not suitable for high performance came from. It's like a bad old wives tale. The pages of Car Craft and Hot Rod mag, along with the drag strip, are loaded with $250,000 machines, sporting Eddy carbs.


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> Is the factory fuel pump going tp be ok with the 800 eddy? The 600 handles it just fine.


The issue with "OEM" fuel pumps is that they're inconsistent. Could be 6, could be 12... The Edelbrock design is such that too much pressure can flood things up. If it's no issue with the 600, than it's a very reasonable assumption that it's within parameters and safe for the 800. 

That being said, one carb might be more temperamental about it than the other... If you're serious about tuning, then add a Marshall fuel pressure gauge and find out what you're running!


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## armyadarkness (Dec 7, 2020)

An0maly_76 said:


> army - Just a thought (and this could be a good thing) perhaps your suspension is just dialed in that well? I have seen cars that just hook and go if everything is perfect.
> 
> Otherwise, I assume you're running premium. Having traveled the continental US coast-to-coast driving trucks, as well as knowing someone who lives in Washington state, I know that certain locations require different octane ratings for altitude (85 octane for example), which affects the oxygen content of the intake air. Perhaps some octane boost or racing fuel would give that extra oomph that is missing?
> 
> I wonder if this might apply to predominantly cooler / colder climates also regardless of altitude. Say, for instance, your engine might do everything expected on 93 octane at say, average temps of 70 degrees, but perhaps average temps of 50 would stifle it somewhat. Also, I found some interesting info on the 670 heads you mention. Maybe all this was already done to yours, but might be worth a read.


I do have Global West upper and lower control arms, front and back, UMI sway bars and coil springs, Global West frame supports, Bilstein shocks with Sphon relocators, and teflon/ delrin bearings replacing all the rubber bushings. If there's one thing my car does well, it's staying planted on the road.

My last 67 seemed much more aggressive, but it had one-wheel-peel... So that's probably why.


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## DustyOldGTO (Jun 26, 2019)

from reading this my impression is that open headers are causing a lean condition. 
check some of your plugs, they should show signs of being quite hot...(burnt white perhaps?)
I would finish your exhaust system and then check again. you can rejet your carb now to have the correct AFR now but it will change again when you close up the exhaust.
You may want/need a different carb in the future but finish the exhaust first.
You are in a change-test-tune loop and if you make too many changes without doing the test & tune it will be tough to dial this in.
I think someone suggested an AFR gauge for tuning...probably a great idea.


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## pandresen (Aug 16, 2021)

Boomstick said:


> So i got my 69 back from the shop on the 18th after having them do the rear main and putting the flowtech headers on. It cost way more than i budgeted due to unforeseen issues so currently i only have open headers with just 2.5" collectors. Before the headers, with factory exhaust and stock style mufflers, the car would spin about 1/4 the way through first from a dead stop at idle by just stomping on the pedal and pull pretty nicely all the way to second gear, then pull well on into 3rd. Now it will burn all the way through first, shift into second, pull like the dickens halfway through second and fall flat on its face up until 3rd, then pull again and flat on its face... I'd say it feels like it lost half the power on the top end... The only thing that changed is the exhaust. Currently since i have an hei, the hood tach doesnt work so my guess is it's dropping off around 4000 to 4500. I've farted around with the timing, the carb and even tried non ethanol fuel and all i can manage to do is make it miss and idle rough or run worse. I did put a new air cleaner on that hit the hood so i put a 1/2 plastic spacer in and took out the 1" aluminum spacer i had originally, but i swapped all that back to the old stuff and nothing changed so im sure the new air cleaner and spacer have nothing to do with this. Its almost like its loading up on the top end but it isn't blowing black smoke nor does it smell likes its loaded up, plus its only a 600 carb so there's that...
> 
> Timing is set at 6deg at idle with the advance disconnected. The vac adv is hooked to manifold vac normally, switching it between port and manifold changes nothing but the idle. my 1970's sears timing light does not have the advance knob so i don't know where its timed with the vac adv hooked up but iirc its in the same place it was before the headers... all adjusting the timing does is make it worse...
> 
> ...


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## pandresen (Aug 16, 2021)

Boomstick said:


> So i got my 69 back from the shop on the 18th after having them do the rear main and putting the flowtech headers on. It cost way more than i budgeted due to unforeseen issues so currently i only have open headers with just 2.5" collectors. Before the headers, with factory exhaust and stock style mufflers, the car would spin about 1/4 the way through first from a dead stop at idle by just stomping on the pedal and pull pretty nicely all the way to second gear, then pull well on into 3rd. Now it will burn all the way through first, shift into second, pull like the dickens halfway through second and fall flat on its face up until 3rd, then pull again and flat on its face... I'd say it feels like it lost half the power on the top end... The only thing that changed is the exhaust. Currently since i have an hei, the hood tach doesnt work so my guess is it's dropping off around 4000 to 4500. I've farted around with the timing, the carb and even tried non ethanol fuel and all i can manage to do is make it miss and idle rough or run worse. I did put a new air cleaner on that hit the hood so i put a 1/2 plastic spacer in and took out the 1" aluminum spacer i had originally, but i swapped all that back to the old stuff and nothing changed so im sure the new air cleaner and spacer have nothing to do with this. Its almost like its loading up on the top end but it isn't blowing black smoke nor does it smell likes its loaded up, plus its only a 600 carb so there's that...
> 
> Timing is set at 6deg at idle with the advance disconnected. The vac adv is hooked to manifold vac normally, switching it between port and manifold changes nothing but the idle. my 1970's sears timing light does not have the advance knob so i don't know where its timed with the vac adv hooked up but iirc its in the same place it was before the headers... all adjusting the timing does is make it worse...
> 
> ...


If I am understanding this correctly, you are running open headers with a 600 cfm carb? You have way too much exhaust flow and at 600 cfm the carb is actually throttling the flow especially at higher rpm. I'm sure the secondary jets are too small. Put something on the end of the headers. I still think you'll a bigger carb at least 700 cfm.


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## An0maly_76 (Dec 25, 2021)

armyadarkness said:


> I do have Global West upper and lower control arms, front and back, UMI sway bars and coil springs, Global West frame supports, Bilstein shocks with Sphon relocators, and teflon/ delrin bearings replacing all the rubber bushings. If there's one thing my car does well, it's staying planted on the road.
> 
> My last 67 seemed much more aggressive, but it had one-wheel-peel... So that's probably why.


Gee, ya think? 🤣


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## Boomstick (Sep 13, 2021)

So since i finished the exhaust and got those super quiet hooker turndown mufflers on it, it seems to be back to the normal "pre headers" power (or lack thereof). in other words, i lost bottom end but it pulls on the top better, like it did before. So im in the process of rebuilding my 3310-10 holley. im going to be putting the glasspacks on in place of the hooker pipes, swapping on the 750 and see where it feels "seat of the pants" wise. I have a feeling ill be happy with the 750 and thrush glasspacks, i bought the 28" ones and tips to turn them down before the axle. 

at some point i need to make a decision on where im going with this car engine wise...

choice # 1: use the 350 that's in it and put on the '69 #46 heads and 068 or 2801 cam. it currently has 71 #94's and stock 2bbl cam...

choice #2: drop in the 557 400 with the 6X-8 heads and whatever cam is in it (i was told its the "largest flat tappet for a pontiac you can buy" whatever that means)... i bought it for this car running on a stand for $1000

choice #3: use the 400 with the small valve #46's and 068/2801

choice #4: dont do anything and wait until the speedmaster heads i got for my bday/xmas "birthmas" show up this spring/summer and then decide which engine to put them on... which would require me to leave it alone for the remainder of winter (doubtful)

sadly i dont have a "good" engine. i have two mediocre engines that restrict how much power i can get out of them. in the meantime, I'm saving up for a butler short block and maybe a built 400th trans... if i can scare the money up for the butler fast enough, the speedmaster heads will go on that and i wont be playing with 350's and glass 400's anymore...lol...


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## Jared (Apr 19, 2013)

You'll want to double check if your #46 heads are earlier castings. Unless I read wrong, the earlier heads had press in studs, which would need to be changed before you can go with a bigger cam.


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## armyadarkness (Dec 7, 2020)

Agreed with Jared. I did that in my teens and I literally had to replace rocker arm studs once a week for the better part of a year. It got old real fast but it was the only option I had at the time


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## Boomstick (Sep 13, 2021)

Jared said:


> You'll want to double check if your #46 heads are earlier castings. Unless I read wrong, the earlier heads had press in studs, which would need to be changed before you can go with a bigger cam.


What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...


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## Boomstick (Sep 13, 2021)

NVM, they came with the 067... 

*Dur.**CL**1.50:1**1.65:1**O.L.**Dur.**CL**1.50:1**1.65:1**Part #*

273112.407".447"54289113.407".447"9779067

maybe stick with the 2800 in the 350?


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## Boomstick (Sep 13, 2021)

1967-69 2bbl V8U269112.5.375".413"47277113.5.410".454"97772541965-76 4bblP273112.407".447"54289113.407".447"9779067

1965-72 HO S288113.407".447"63302119.407".447"9779068

so the car currently has the 254 cam which has more lift on the exhaust than even the 068, so wouldn't it be safe to assume that the intake studs would handle the same lift? 

which brings me to one of my other ideas, 1.65"s on the intake valves instead of a complete cam swap... leave the 254 in the car, put the $$$ towards something else...


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...


iN MY OPINION, DON'T EVEN BOTHER GIVING YOUR BUSINESS TO PLACES LIKE THAT. Sorry for the caps lock...

It always ends poorly. But yeah, my 66 Lemans with a 350 and mild cam, broke press in studs CONSTANTLY!


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## armyadarkness (Dec 7, 2020)

All of it is subjective, but do "whatever you can". Whenever buying bicycles, guitars, or doing car repairs, it always pays to do the best you can.

Meaning, if you can only afford oil, but not a filter, than leave the filter and change the oil... but that';s obviously not what you'd do if you didn't have to.

Same here... Youre a Pontiac guy. Therefore, you need heads with screw in studs. Either buy them, or get yours done... and if you're doing all of that work, then put in the cam that you want as well. It's not hard to make a lot more power than you need with a 350. Do a little gasket matching, square away your fuel and ignition... and a 350 is a ton O fun


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## Jared (Apr 19, 2013)

Boomstick said:


> What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...


It could be OK until it isn't. I'd hate for you to find out the hard way on this. You should be able to find a machine shop to tap the heads for a set of screw in studs. I can't imagine the cost would be too high. Problem may be finding a shop with time available. I waited 6 months for a short block build and 9 for the heads, and these were ordered close to 2 years ago now. I was told that those shops backlogs went way up when the pandemic hit. Evidently, folks uncovered their projects.

One suggestion would be to drive it as is and get your project on the que at a local shop. Pull the heads when your turn comes up to minimize the time your car is off the road. Side note, A lot of these machine shops operate the old school way. Free advice would be to pick up the phone.


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## Boomstick (Sep 13, 2021)

What about drilling and pinning the studs? I just read an article about doing just that and found a kit for it...

BTW the 46's are not on the engine yet...









Press-In Rocker Arm Stud Pinning Kit


Add positive retention to your rocker arms with this complete stud pinning kit. Rocker stud pins are cheap insurance for race engines that require stock cylinder heads, or for mild street engines built on a budget. Most factory cylinder heads utlilize press-fit rocker arm studs, which can pull...




www.speedwaymotors.com


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## armyadarkness (Dec 7, 2020)

Pinning would not have helped me. All of my studs "snapped" where the threads began.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Pinning would not have helped me. All of my studs "snapped" where the threads began.


geez, what cam were you running?

I spent all night (i came in at midnight) reading articles and watching vids of how to pin the studs. i think im going to go that route with these 46's. worse case, i break a stud and end up putting the 94's back on before the speedmasters show up. once i get the aluminum heads, ill probably just sell the 46's, 94's and the 6x-8s off the 400 and just keep the 400 short block as a spare incase i blow the 350...

in reality, at this point i'd be fairly happy with the 330hp the 350ho boasted in 69, which is what i thought this motor was when i first bought the car. my motor is the 265hp with the 2bbl, 254 cam and #47 heads with cast exhaust manifolds. currently im running a 600 summit carb, edelbrock performer rpm intake, ceramic coated flowtech headers and #94 heads. i may go ahead and just toss the 46's on, put 1.65's on the intake valves and just be done with it until i get the speedmasters and pick a cam then...my holley 750cfm 3310-10 may be going on today, if i ever get off work that is...


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## Boomstick (Sep 13, 2021)

i didn t get off until noon so the holley is still on my workbench maybe today when i get off duty at 8am ill get it on...


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## BearGFR (Aug 25, 2008)

So, if you break off a rocker stud "at the wrong time" you're going to lose more than just the stud. If it happens at RPM, it's not unheard of for it to also shoot the pushrod --- through the valve cover and through the hood. Not to mention putting metal fragments down into the engine where they can be picked up, sent through the oiling system, taking out your bearings. Are you sure you want to take those chances? 

I'd never try to build a Pontiac engine with even slightly "more" than a factory spec cam unless it had screw in, 7/16 rocker studs with poly-locks.

My .02

Bear


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> geez, what cam were you running?
> 
> I spent all night (i came in at midnight) reading articles and watching vids of how to pin the studs. i think im going to go that route with these 46's. worse case, i break a stud and end up putting the 94's back on before the speedmasters show up. once i get the aluminum heads, ill probably just sell the 46's, 94's and the 6x-8s off the 400 and just keep the 400 short block as a spare incase i blow the 350...
> 
> in reality, at this point i'd be fairly happy with the 330hp the 350ho boasted in 69, which is what i thought this motor was when i first bought the car. my motor is the 265hp with the 2bbl, 254 cam and #47 heads with cast exhaust manifolds. currently im running a 600 summit carb, edelbrock performer rpm intake, ceramic coated flowtech headers and #94 heads. i may go ahead and just toss the 46's on, put 1.65's on the intake valves and just be done with it until i get the speedmasters and pick a cam then...my holley 750cfm 3310-10 may be going on today, if i ever get off work that is...


Well, I was 19 at the time, now Im 53... so I have no idea what cam it was, but the car was fast and fun! I was told that it was a very mild cam... 

As I understand it, the weak point of press in studs is NOT that they pop out, it's that they snap where they are machined down to the threads. It literally happened constantly. I vividly remember finally going to the junk yard and pulling a bunch of spares to carry.

Im no performance guru, but that was my experience. Installing threads is so easy, I cant see any other way being worth it... and this is assuming that the heads are so awesome that they're worth it.

Then every GTO I had after that Lemans had 670's with screw in studs, so I never had to deal with it again... but back in 95 when I built my first 67, I remember the builder commenting that I had the preferred setup, and I recall being happy! Wasnt looking to revisit the old stud pulling days!!


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## armyadarkness (Dec 7, 2020)

BearGFR said:


> So, if you break off a rocker stud "at the wrong time" you're going to lose more than just the stud. If it happens at RPM, it's not unheard of for it to also shoot the pushrod --- through the valve cover and through the hood. Not to mention putting metal fragments down into the engine where they can be picked up, sent through the oiling system, taking out your bearings. Are you sure you want to take those chances?
> 
> I'd never try to build a Pontiac engine with even slightly "more" than a factory spec cam unless it had screw in, 7/16 rocker studs with poly-locks.
> 
> ...


That's where I got jammed up on my 67 build, back in the 90's. The terminology between 7/16 and 3/8, so Summit sent me the wrong rockers. The stud itself is 7/16, but the poly lock is only 3/8, correct?


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## BearGFR (Aug 25, 2008)

armyadarkness said:


> That's where I got jammed up on my 67 build, back in the 90's. The terminology between 7/16 and 3/8, so Summit sent me the wrong rockers. The stud itself is 7/16, but the poly lock is only 3/8, correct?


 Factory Pontiac rocker studs, both pressed in and screwed in, are "bottlenecked" down to 3/8 at the top for the rocker nuts and as you found out, they really like to break off at the neck. The studs I was talking about are 7/16 all the way up, and are a lot stronger.


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## Jared (Apr 19, 2013)

To add to this. Swapping out the bottle neck style make the valve train adjustable rather than just torque to spec and call it a day. If your going to be running a bigger cam shaft, you really want to do this upgrade. When these engines let go at RPM, it is never a cheap fix to put them back together.


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## Boomstick (Sep 13, 2021)

Wouldn't a stud girdle solve the bottleneck breakage problem?


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## armyadarkness (Dec 7, 2020)

BearGFR said:


> Factory Pontiac rocker studs, both pressed in and screwed in, are "bottlenecked" down to 3/8 at the top for the rocker nuts and as you found out, they really like to break off at the neck. The studs I was talking about are 7/16 all the way up, and are a lot stronger.


Glad I mentioned it then! Not sure which I have!!!


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> Wouldn't a stud girdle solve the bottleneck breakage problem?


Even if it did, all you'd be doing is numbing a symptom, which you'd be better off curing. Like putting a 2bbl and header on a 194 Straight Six, or drag slicks on an open rear.

7/16 screw in studs are the best. 3/8 screw in studs are the next best (at least they can be upgraded), push in studs suck. 

Your aspirations should be for the best valve train.


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## Boomstick (Sep 13, 2021)

Yeah, I've just been trying to avoid taking these to a machine shop. I kind of want to do it all on my own. I've read that I can pull the studs, tap them myself and helicoil the holes so I'll probably just go that route even though it's a lot of work. I only paid $300 for these heads which should bring my compression up to where it needs to be too run the 2801 cam in this 350.

Once the speedmasters show up I'll have to make a decision between putting them on this 350 or on the 557... I'm thinking the 350 just so long as shrouding isn't a problem. If I have to pull the 350 to chamfer the block I might as well just drop the 400 in...

In the meantime I'm trying to talk my better half into letting me finance a Butler short block by telling her both motors are garbage and if she wants to go to cruise ins and the beach and really enjoy the car, the car needs a Butler 428


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## Boomstick (Sep 13, 2021)

after talking it over with a pontiac guy here locally and from what ive read hear and been told by you good folks, I've decided im going with the 068/spc-7 in the 350 with the 1969 #46 heads and stock rockers, rpm intake and 750 holley... save the 1.65's for the 400... he also said to "go ahead drill and pin the studs while they are off the engine if you're that worried about it" and "it (the 350) will never be a 400"...

its only another $350 give or take and im tearing the motor down pretty far to put the heads on so why not right? plus i can sell the 94's to recoup some of the $$$... not much but a little lol

would the 557 casting 400 be safe with the 2801, 1.65's, speedmaster heads, rpm intake and 750 carb without a rapid dissemblance of parts, unassisted?

or maybe ill just resell the 557 the way it is and put the $$$ towards the butler short block i want and run the 350 in the meantime...hmmmmm....

i think that might be the best idea yet...


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## Jared (Apr 19, 2013)

Boomstick said:


> or maybe ill just resell the 557 the way it is and put the $$$ towards the butler short block i want and run the 350 in the meantime...hmmmmm....


Heads up. Butler, and all other Pontiac builders, will be a year out on their supply. Butler may be even further back. Another option would be to contact Len Williams. I built my engine using his 455 short block (actually is a stroked 400 that measures in at 461 with the overbore). May save you a bit of cash compared to Butler but will still have a long wait. I ordered mine in early July 2020 and it showed up at my door in December of the same year. I had heard he had a longer wait now.

Moral of the story, if you really want to go that route, plan ahead. And if it's running, don't tear the car apart until the new engine arrives.


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## Boomstick (Sep 13, 2021)

Jared said:


> Heads up. Butler, and all other Pontiac builders, will be a year out on their supply. Butler may be even further back. Another option would be to contact Len Williams. I built my engine using his 455 short block (actually is a stroked 400 that measures in at 461 with the overbore). May save you a bit of cash compared to Butler but will still have a long wait. I ordered mine in early July 2020 and it showed up at my door in December of the same year. I had heard he had a longer wait now.
> 
> Moral of the story, if you really want to go that route, plan ahead. And if it's running, don't tear the car apart until the new engine arrives.


yeah, ive decided im leaving the 350 in, keeping the 557 400 as a spare and saving $$$ for the butler... once it arrives i'll swap it in and maybe sell the 557... perhaps a clean 428 will come up for sale near me in the meantime (which is what i really want). the car runs good now and i can squeeze a little more out of it with what i already have...


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## armyadarkness (Dec 7, 2020)

I like 350's. My 66/350 was more fun than most other cars I had. 4bb, headers, cam, ignition, gears... and a 350 will blow most everything off the road.


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## Jared (Apr 19, 2013)

I had a friend in high school who built up a 72 LeMans with a 350 and an automatic. When I say built up, I mean he had a fresh rebuild, stock heads, and all the typical bolt ons. It was a one wheel peel but would put down more rubber than you can imagine. Like 2 -3 city blocks just nailing it from a stand still. Typical of a high schooler. He had 3 accidents with it within a couple months and then blew it up.


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## armyadarkness (Dec 7, 2020)

Yesterday on FB some Pontiac Club had a video up of a guy doing a burn out in a 67. He power braked it for quite a bit and then only spun for maybe 20 feet.

Im always complaining about my power, but at least with 3:36's, my car roasts the tires, without brakes, and then chirps 2nd and 3rd.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Yesterday on FB some Pontiac Club had a video up of a guy doing a burn out in a 67. He power braked it for quite a bit and then only spun for maybe 20 feet.
> 
> Im always complaining about my power, but at least with 3:36's, my car roasts the tires, without brakes, and then chirps 2nd and 3rd.


and what motor is hiding under the hood? 

im running 3:23's out back on a one legging "safety trak"... the tag on the diff says use limited slip fluid so i assume its a safety trak... eventually its getting 3:42's or 3:73's and a luchbox locker but im doing the motor first, then trans, then rear...


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## Boomstick (Sep 13, 2021)

or...





__





Pontiac 326-455 V8 – Single Supercharger Kit | TorqStorm


Complete kit will mount one TorqStorm® Supercharger to a 326-455 Pontiac V8 engine and 1967-1969 F-Body cars (please select proper kit from the options below).




torqstorm.com


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> and what motor is hiding under the hood?
> 
> im running 3:23's out back on a one legging "safety trak"... the tag on the diff says use limited slip fluid so i assume its a safety trak... eventually its getting 3:42's or 3:73's and a luchbox locker but im doing the motor first, then trans, then rear...


My car has its original 400 with 670 heads. Rebuilt .030 over with a full roller Ram Air valve train. The 336's were also factory, but it was an open rear car. I put in an Auburn Posi


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## armyadarkness (Dec 7, 2020)

Boomstick said:


> or...
> 
> 
> 
> ...


Only problem with stuff like that, is that the advertised cost is never the real cost. By the time you get to the end of that rabbit hole, you'll have spent another $1000 and a few months of time.


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## Boomstick (Sep 13, 2021)

armyadarkness said:


> Only problem with stuff like that, is that the advertised cost is never the real cost. By the time you get to the end of that rabbit hole, you'll have spent another $1000 and a few months of time.


yeah, right off the bat ill need a blow through carb and probably a shorter intake than the eddy rpm which barely clears the hood now... not that plenum volume is a concern with a blower. however it would give me an excuse to leave the low compression small valve #94 heads on the the car and just push more boost. sell the rpm intake, the summit 600, #46 heads and the 557 to recoup some cost... 

maybe a winter project for next year...


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