Longer head bolts needed for A/C bracket on '66 389 engine?
 

I yanked the ol' 389 out of my 1966 GTO convertible and intend to restore it to its original configuration. I've been gathering parts for years and plan to install:

- 093 cylinder heads
- Correct camshaft (GM 9779068) & lifters
- Correct timing chain cover (GM 9783130)
- Tri-power intake & carbs (thanks, pontiactripower.com)
- A/C system brackets and compressor (no A/C stuff on engine now)

I have questions about cylinder head bolts:

1. Can I re-use the existing head bolts (092 heads on engine now) or do I need to buy new bolts?

2. The A/C bracket (GM 9788304) attaches to engine using two cylinder head bolts. Do I need two longer bolts to accommodate the bracket?

3. If new bolts or longer bolts are needed, what should I get and where's the best place to buy them?

I look forward to your guidance and appreciate all advice!

The original two bolts have studs on top of them. If you are doing a stock rebuild then you should have no trouble re using them.

I think you and I are talking about two different A/C brackets, Tod. The bracket that I want to attach to my 389 is a heavy, forged part. The bracket's bolt holes are 1/2-inch diameter -- exactly as needed to accommodate an actual head bolt; not a smaller stud.

I measured the depth of the mounting holes on the bracket. The front hole is 1 inch deep and the rear hole is 2 inches deep. It's now obvious to me that my existing head bolts are way too short to mount this bracket. If I can't locate the correct Pontiac head bolts, guess I'll buy a couple of Grade 8 bolts. You'd have to look hard to see them after the A/C compressor is mounted on the bracket.

Here are a couple of pics that show the A/C bracket I'm talking about:


http://mywebpages.comcast.net/Exit32/ACbracket.jpg


http://mywebpages.comcast.net/Exit32/HoleDiameter.jpg

What he's saying about the bolts is the head will bottom on the bracket just like a regular bolt. But have a stud on the head for what ever reason like many other bolts on these engines. I took that bracket off mine and went looking for shorter bolts. I'll take a look tomarow if I can hunt them up easy you can have them for the amount of shipping if you still need or want

Sorry for my earlier post. They are not studs. They are 4 5/8" in length. I pulled out my a/c brackets and took these two photos:

http://emob713.photobucket.com/album...g?t=1276744003

http://emob713.photobucket.com/album...g?t=1276744075

Goto: http://www.inlinetube.com/ and look at the GTO Catalog on page 10. They have all of the A/C compressor bolts listed, but these long head bolts. Maybe they have access to the longer head bolts. I'm sure that someone on here will have them if they are not available from the repro companies.

Again - sorry for the bad info posted earlier.

I HAVE EXACTLY WHAT YOU NEED.
ONE OF THE BOLTS HAS A THREADED STUD ON IT.
I WILL POST A PICTURE LATER.

I just looked at my car (66 w/fac. a/c) and the rear bolt on that bracket does have the stud on top. Nothing attached to it..maybe they were to be used for other mounting of equip.? Calif. AIR, etc.?

Thanks for all the replies here. I should have taken a closer look at the A/C bracket before I posted my questions because it's very obvious that I need some longer bolts to make this work.

I really appreciate the photos you posted, Tod. Very helpful. Now that I know that bolt length is 4-5/8 inches. I can get a couple of Grade 8 bolts locally, or buy Pontiac bolts from someone here.

I'll be assembling the engine over the next week or two, so if FFD or ryan389 has the correct Pontiac bolts, let's make a deal.

Long Head Bolts
 

Exit32: Here are the pictures that I promised you. Let me know if this is what you want. PM me or post a reply on this thread.

Thanks.

Thanks for the pics, ryan389. I sent a PM to you.

Found mine in the bracket box. Little bit different than Ryans. Stud bolt the same the other has an extended head a inch or so with a tapped hole with bolt. Where the dip stick tube bolted to. Talked to someone else said possible from a 68 set up

Thanks for looking at your bolts, FFD. I made a deal with ryan389, and I'm good to go with a couple of long head bolts on the way.

I appreciate all the replies and info here. Chances are good that I'll have more questions for you experts as I restore my 389 to its factory configuration.