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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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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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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
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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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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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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Discussion Starter · #46 ·
Wouldn't a stud girdle solve the bottleneck breakage problem?
 

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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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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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Discussion Starter · #49 ·
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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Discussion Starter · #50 ·
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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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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Discussion Starter · #52 ·
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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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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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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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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Discussion Starter · #56 ·
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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Discussion Starter · #57 ·
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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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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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Discussion Starter · #60 ·
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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