# Head Bolt for AC Bracket



## armyadarkness (Dec 7, 2020)

I'm removing the dealer installed air off of my 67/ 400. There's a big ugly bracket on the front passenger side, and it's held on with two head bolts. Can I simply remove them and replace them?


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## nick rice (Nov 10, 2014)

Do you know if they used longer bolts? I'm no expert but I'd play it safe and deduct the thickness of the ugly bracket from the threads with shorter head bolts if the others are shorter.

Sent from my SM-G970U using Tapatalk


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## Old Man Taylor (May 9, 2011)

I'm not aware of any factory brackets that go under the head bolts. They're usually studded bolts.


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## armyadarkness (Dec 7, 2020)

nick rice said:


> Do you know if they used longer bolts? I'm no expert but I'd play it safe and deduct the thickness of the ugly bracket from the threads with shorter head bolts if the others are shorter.
> 
> Sent from my SM-G970U using Tapatalk


The bolts are definitely longer, so I would need to compensate for that. My fear is interfering with the torque. I'll take a picture and post it.


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## armyadarkness (Dec 7, 2020)

Old Man Taylor said:


> I'm not aware of any factory brackets that go under the head bolts. They're usually studded bolts.


Not factory... Dealer installed air! It's under the bolt heads!


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## armyadarkness (Dec 7, 2020)




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## pontrc (Mar 18, 2020)

OMT is right that is a stud bolt


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## AZTempest (Jun 11, 2019)

I currently have the heads pulled on mine with the same bracket. I'm at work right now but tomorrow I can double check the proper size you will need for the head bolt without the bracket.


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## armyadarkness (Dec 7, 2020)

pontrc said:


> OMT is right that is a stud bolt


Yes... but doesn't a typical stud bolt have the accessory mounted "on the stud", not beneath the bolt? I want that bracket off, and my question is, can I just remove those bolts and replace them with the correct ones, or will that screw up the head gasket seal?


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## armyadarkness (Dec 7, 2020)

AZTempest said:


> I currently have the heads pulled on mine with the same bracket. I'm at work right now but tomorrow I can double check the proper size you will need for the head bolt without the bracket.


Is yours mounted the same way?


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## Old Man Taylor (May 9, 2011)

The bracket they installed looks too thick for the stud on the bolt. I would look for some hardened washers to go under the bolt heads. Otherwise you're going to have to take the bolts out. measure them, and try to find some as much shorter as the thickness of the bracket. If you do them one at a time the head gasket should be fine. But I wouldn't do more than one at a time. What you can do is drop in a long rod and measure how far down it goes. The measure the bolt from the end to the bottom of the head. Maybe you will get lucky. They might have just reused the original bolts, even though that not the correct way to do it (IMHO).


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## AZTempest (Jun 11, 2019)

armyadarkness said:


> Is yours mounted the same way?


The same type bracket but I can't recall if my head bolts are exactly like yours. I'll check when I get home. I doubt you could do one at a time as suggested as you need to get the bracket out of the way first. I'm personally the guy who would just pull them and torque the rear one first then the front.


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## BLK69JUDGE (Jun 10, 2010)

Hello
those look to be correct 67 68 ac head bolts ,,,, seen em with and without the stud on top .. 67 n early on the 68's mostly with the stud
just had 2 later a march and april 68 ac cars and they were studless..
if you need a pair of originals non ac head bolts I can mail you a pair ,,, for deleting the bracket ... 
what is the foundry mark on the top of your smooth heads... is it a sunburst pattern or a bullseye ??

Scott


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## AZTempest (Jun 11, 2019)

Here is my setup. bolts on the right are for use with the bracket. Ones on the right would be for use without. As for screwing up the head gasket seal, not sure. 

Jim


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## Old Man Taylor (May 9, 2011)

With the bolts being on the front and outside, you’re probably OK. take them out in reverse order (front first), and install the front one last. I’m kind of anal about that sort of thing.


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## armyadarkness (Dec 7, 2020)

Thanks for all of the input, everyone. 35 years later... I've done it all, but I never really got into engine internals (I'm more of an engineer), hence my concerns about the cam and head bolts. The original owner did say that the AC was dealer installed, using the factory AC bracketry, but I can't verify that. I'll first attempt to get the engine builder to do it for me... but he's not answering the phone or returning calls, so he's either very busy, or bathing in corona-bucks and not wanting to work.


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## armyadarkness (Dec 7, 2020)

BLK69JUDGE said:


> Hello
> those look to be correct 67 68 ac head bolts ,,,, seen em with and without the stud on top .. 67 n early on the 68's mostly with the stud
> just had 2 later a march and april 68 ac cars and they were studless..
> if you need a pair of originals non ac head bolts I can mail you a pair ,,, for deleting the bracket ...
> ...


Thanks! I'll keep you posted. Where is the foundry mark? And what will it tell me?


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## Old Man Taylor (May 9, 2011)

armyadarkness said:


> Thanks for all of the input, everyone. 35 years later... I've done it all, but I never really got into engine internals* (I'm more of an engineer)*, hence my concerns about the cam and head bolts. The original owner did say that the AC was dealer installed, using the factory AC bracketry, but I can't verify that. I'll first attempt to get the engine builder to do it for me... but he's not answering the phone or returning calls, so he's either very busy, or bathing in corona-bucks and not wanting to work.


What kind of engineer? My training was in electronic engineering, and I worked in the computer field for 45 years.


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## armyadarkness (Dec 7, 2020)

Old Man Taylor said:


> I’m kind of anal about that sort of thing.


Yeah, me too. Which is why the bracket has to go!


Old Man Taylor said:


> What kind of engineer? My training was in electronic engineering, and I worked in the computer field for 45 years.


Mostly CAD and Digital Imaging. A lot of mechanical and structural, even some electrical. Currently, I still do digital imaging for a luxury yacht manufacturer. I shoot the boats with a 3D laser and/ or use crime scene analysis software, to produce cad files of marine parts. I'd rather make GTO parts!


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## Old Man Taylor (May 9, 2011)

I also liked getting away from my profession. Outside of work had nothing to do with my profession.


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## Gtowally (Jan 19, 2019)

armyadarkness said:


> Is yours mounted the same way?


Once that head was torqed and ran I wouldnt have a problem replacing bolts and retorqing (sorry fellas, having a problem with the spelling of this word..old age catching up)


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## armyadarkness (Dec 7, 2020)

BLK69JUDGE said:


> Hello
> those look to be correct 67 68 ac head bolts ,,,, seen em with and without the stud on top .. 67 n early on the 68's mostly with the stud
> just had 2 later a march and april 68 ac cars and they were studless..
> if you need a pair of originals non ac head bolts I can mail you a pair ,,, for deleting the bracket ...
> ...


Scott, where is this mark? I spent 3 hours last night, researching head bolts, and as usual, the internet has ruined everything logical. I finally rolled the dice on an entire set of ARP head bolts, but aside from the $100 tag, I'm not sure that they'll fit and I'm not crazy about mixing and matching


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## BearGFR (Aug 25, 2008)

ARP makes several different bolt sets for Pontiac heads. They vary based on which heads they're for, and the differences are in bolt length. Round port factory heads, like Ram Aiv IV, 455SD, etc. require the bolt that goes between the center exhaust ports to be slightly longer because those heads are thicker there than the iron D-port heads. Different aftermarket aluminum heads also need different length bolts in various locations for similar reasons. However as far as I can remember without looking it up, all factory D-port heads use the same ARP bolt set. All their stuff is good though. Use the torque specs ARP specifies, not the factory ones, and DO use ARP's Ultra-Torque installation lube.

Bear


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## armyadarkness (Dec 7, 2020)

BearGFR said:


> ARP makes several different bolt sets for Pontiac heads. They vary based on which heads they're for, and the differences are in bolt length. Round port factory heads, like Ram Aiv IV, 455SD, etc. require the bolt that goes between the center exhaust ports to be slightly longer because those heads are thicker there than the iron D-port heads. Different aftermarket aluminum heads also need different length bolts in various locations for similar reasons. However as far as I can remember without looking it up, all factory D-port heads use the same ARP bolt set. All their stuff is good though. Use the torque specs ARP specifies, not the factory ones, and DO use ARP's Ultra-Torque installation lube.
> 
> Bear


Thanks Bear. I don't mind spending $100 on two bolts, but I want the job to go smooth.


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