1969 427 aluminum cylinder head bolt markings

[Tim S.]

I would like to know the correct original head bolt markings for a 69 model year 427 engine with aluminum heads. My engine has two markings, the short bolts have a raised cross (+) ; the long bolts
have no marking at all. They are both flanged.
Thank You

[Enzo C.]

Re: 1969 427 aluminum cylinder head bolt markings

Hi Tim, this is a good question for Rich Pasqualone... He is the bolt King ... He is also a NCRS member

[Joe L.]

Re: 1969 427 aluminum cylinder head bolt markings

I would like to know the correct original head bolt markings for a 69 model year 427 engine with aluminum heads. My engine has two markings, the short bolts have a raised cross (+) ; the long bolts
have no marking at all. They are both flanged.
Thank You

Tim------


Aluminum head big blocks, both L-88 and L-89, used the same head bolts as those with cast iron heads. Only ZL-1 used different head bolts.

All of the original big block head bolts, both short and long, I have seen had a raised cross on the head, were flanged style, and were untrimmed (i.e. "indented head"). Also, a small point: on original and old SERVICE bolts the ends of the cross extended all the way or virtually all the way to the perimeter. On later GM SERVICE bolts the ends of the cross were shorter.

It's possible that some original bolts lacked the cross or other marking. However, I HIGHLY doubt it. Your unmarked head bolts might be aftermarket replacements.

[Tim S.]

Re: 1969 427 aluminum cylinder head bolt markings

Joe Thank you

[Wayne M.]

Re: 1969 427 aluminum cylinder head bolt markings

Tim -- And don't forget the hardened washers under each head bolt.


Here's another view of head bolts -- can't recall the discussion at the time.

[Tim S.]

Re: 1969 427 aluminum cylinder head bolt markings

Wayne Thank you can you tell me which ones in the picture is the short bolt , I think it is the one with the C on it.
I assume all these bolts use a 5/8" socket for the head. Also where would I get the hardened washers?

I appreciate your help.

[Joe L.]

Re: 1969 427 aluminum cylinder head bolt markings

Wayne Thank you can you tell me which ones in the picture is the short bolt , I think it is the one with the C on it.
I assume all these bolts use a 5/8" socket for the head. Also where would I get the hardened washers?

I appreciate your help.

Tim------


Washers are GM #3899696 and remain available from GM.

[Tim S.]

Re: 1969 427 aluminum cylinder head bolt markings

Parts dealers say 3899696 discontinued, a few are still scattered around so I managed to find 32.

Thanks