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Discussion Starter #1
A pressed in rocker arm stud bolt broke on my 1965 389 head. I got it out and started looking for a few online. I can't find any press in studs anywhere. I want to drive this (new to me) beautiful car a bit before pulling the heads and having them threaded to accept screw in studs. Do any of you know who might have a few available? Mine is a bottleneck 3/8 threaded top and 7/16 press in base. Total length approx 2.042 inches. A straight 7/16 would also work. I also would like to replace a couple of push rods that dont pass the roll on the flat surface test. They are 8.625 inches long and .3 inch diameter. Any leads are appreciated.
 

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Call Butler Pontiac Performance in Tennessee, they will help you out, and they have all those pushrods sizes in stock, they ship fast and will advise you on that rocker.

You may have top tap it and put in heli-coil threaded insert and then threaded stud.....

Good luck
 

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Discussion Starter #4
Butler hasn't carried any press in bolts for a long while. I am checking with machinists in my area.
 

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Yeah, I was thinking more of you tapping the stud with a thread tap and adding a helicoil insert and then using a screw in stud.

That is how they often do the screw in studs.....from original press in because of the size.
 

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Butler hasn't carried any press in bolts for a long while. I am checking with machinists in my area.
If you REALLY want a replacement press-in stud, my guess is that there are lots of Pontiac guys on some of the Pontiac forums & FB pages who will give you some for just enuff to pay for the postage to mail it.

There are lots of guys who have had their heads converted to screw-in studs, and may have kept the old studs. Probably lots of other guys who have some of the junk heads they could pull a stud out of, for you.
 

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Discussion Starter #7
Does anyone have a few of these studs that they will part with? This warm weather in Ohio wont last much longer and I would love to drive my new Goat before the snow flies.
 

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Does anyone have a few of these studs that they will part with? This warm weather in Ohio wont last much longer and I would love to drive my new Goat before the snow flies.

Just to close out this post, I had a junk 1972 head I thought I tossed and I pulled out a couple of rocker arm studs and had a couple pushrods lying around that I sent to jjminor. He was going to have a buddy swing by and help with the installation and get the engine sorted out. Hopefully all goes well and another Pontiac is up and running. :yesnod:
 

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Discussion Starter #9
A public thank you to Jim for his help in getting my GTO ready to run again. My plan is to eventually disassemble these heads and have the rocker bosses threaded and also see if we can make it a little more gas friendly. It all depends on what we find. I will post the results. Men like Jim give this forum access to a wealth of knowledge and it is much appreciated.
 

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Discussion Starter #10
Update: Hoping to lower the CR on this 389 to run well on pump gas I decided to pull the heads and see what is in this engine. I found that it is bored .060 over, has standard pistons with 8 valve reliefs and a notched cylinder wall. I am told that the 400 heads will still not match up and laying a 400 head gasket on my 389 will show me why. With that in mind I will finish pulling the engine and have cc volume calculated,dished pistons installed, threaded rocker studs installed and cam and valve springs installed to compliment the lower CR. I want it to have good street manners yet close to original torque. Any comments or ideas on cam grind?
 

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Not worth fixing a pressed in stud. Put in screw ins. One popped out on my 67 many years ago, and I was able to drill and drive in a roll pin temporarily, or was it a taper pin. Can't remember. last set of heads drilled and tapped cost me 300. Don't know what they would get today.
 

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I think I remember reading of guys using 400 heads on 389 blocks. One guy even said he'd run a fairly decent cam, using the 389 pistons.

I assume what you are referring to is the location of the cyl chamfers in the block, maybe ? I don't think that will be a problem, with small valve 350 or 400 heads. But, I've never used a 389 block, so all I know if what I've read.

Guessing there are a few guys here who have tried 400 heads on a 389 block. Maybe some will chime in & post their results.

I think those 8-relief pistons have an 11cc volume. Most have a bevel around the edge, which reduces CR. Then, if they're in the hole very far, you're CR may be closer to 9:1 than 10:1.

https://www.summitracing.com/parts/slp-411np60/overview/make/pontiac

The cheaper 400 gaskets are about .045 thick. I don't know if cheap 389 specific gaskets are even still sold.

https://www.jalopyjournal.com/forum/threads/lets-discuss-389-pontiac-headgaskets.804753/#post-8933248

https://www.jalopyjournal.com/forum/threads/lets-discuss-389-pontiac-headgaskets.804753/#post-8936977

Butler shows these gaskets to fit 389 & early '67 400's. I assume that means they allow for the different cyl chamfer location.

https://butlerperformance.com/i-24453585-butler-performance-pontiac326-389-421-and-early-1967-400head-gasketset-2spm-19375-2.html?ref=category:1234803

Then of course, there are the high dollar Cometic gaskets. They can make anything you want.

https://butlerperformance.com/i-26175442-cometic-mls-4-200-bore-040-thick-chamfered-for-pontiac-389-or-421butler-spec-set-2com-h4366sp3040s.html?ref=category:1234803

If you switched over to bigger chamber heads, the valves would be farther from the pistons. That should provide more valve to block clearance. I'm assuming that the larger chamber, small valve heads, such as '74 #46 350 heads should work just fine on a 389 block. And, since the block has been bored .060 over, there should not be any valve to block clearance problem, at all. I could be wrong. But, I don't think so. All the Pontiac heads produced after the middle of May, 1973 had screw-in studs. So, any #46 head made after that date will have screw-in studs.

If you get the CR down to well below 9:1, a small Voodoo will help increase cyl pressure.

https://www.lunatipower.com/voodoo-hydraulic-flat-tappet-cam-pontiac-v8-256-262.html

The ramps on this Howard's are not quite as steep.

https://www.summitracing.com/parts/hrs-410021-12/overview/make/pontiac

If you go with closer to 9.5:1 CR, an 068 clone, such as the Melling SPC-7, will work. The Summit 2801 is similar, but has more lift. A Lunati 10510312 has a little more duration, @ .050 lift.
 

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Discussion Starter #13
Great information to work with. I will continue to evaluate the current set up and determine what changes need to be made. I can either work with what I have, switch heads, start over with a new rebuild, or swap out to another engine. Rebuilding with a known Pontiac rebuilder will cost north of $11,500.00. I keep looking at this very clean 389 and wondering what was done right and what (if anything) was compromised along the way. Once I figure that out then my decision will be easier. I will spend the rebuild dollars if necessary but not if this engine just needs a few tweaks.
 

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"...Rebuilding with a known Pontiac rebuilder will cost north of $11,500.00...


Yeah, there are several of the big name guys who charge that much. You can buy from Len Williams, pay shipping, & spend thousands less. Obviously, he can add upgrades, for a little more.

400 Long Block

455 Long Block

Don't know which of the big name guys sell the cheapest. If you can assemble yourself, you might save quite a bit by going with a ready-to-assemble short block, from Butler, and have your heads done, without porting, closer to home.

https://butlerperformance.com/i-24452991-butler-performance-custom-short-block-kit-400-block-434-494-cu-in-unassembled.html?ref=category:1234783

Here's a few builders, besides KRE & Butler.

https://www.facebook.com/PaulKnippensMuscleMotors/

https://www.dcimotorsports.com/

http://www.spottsperformance.com/

Sandoval sells a budget stroker short block for $5k plus shipping.

https://www.sandovalperformance.com/engines

If you'll check with some Pontiac clubs in some of the larger cities in your area, they may be able to hook you up with somebody who can build cheaper, since there are lots of guys who can't spend, $10k+ for an engine.

Then there are the Ebay sellers. This guy has 100% positive feedback, for whatever that's worth. The 400 he advertises has dome pistons, to increase CR, with the 6X heads. But, I assume he could build with SP L2262F flat tops. You have to also be careful when buying a 400, because the cheapest & most easy to find block is the infamous "557" block. Wouldn't pay $5k or more for an engine built using a 557 block. Others can if they choose. to. Every time I mention this somebody always says those block are fine up to 400hp, & others will say they made much more & never had any problems at all. Just be warned, LOTS of those blocks have cracked the main webs at one of the main cap dowel pin holes.

https://www.ebay.com/itm/Rebuilt-400-Pontiac-HP-Complete-Engine-6X-heads/174058286540?hash=item2886aeadcc:g:zfMAAOSwAa5ahzHr

https://www.ebay.com/itm/Rebuilt-455-Pontiac-Complete-Engine/153530400005?hash=item23bf1ffd05:g:pEgAAOSwf5Ba9HXq
 

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Discussion Starter #15
I am checking out all this information and some leads from local sources and hopefully will get the build I want at a reasonable price. Time will tell.Thanks
 
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