L89 head bolt torque

[Belair62]

Whats the proper torque for these aluminum heads anyay ??

[Mr70]

Short Bolts-65 Foot Lbs.
Long Bolts-75 Foot Lbs.

[Belair62]

[nuch_ss396]

Bob,

Are you using the hardened steel washers with the head bolts?

Steve

[Belair62]

No..they look like stock head bolts not ARP type

[nuch_ss396]

Bob,

Stock L/89 head bolts used the washers. I investigated this a couple
of years ago for an L/89 project. I talked to a number of unrestored
L/89 owners ( NCRS.ORG ) and Jerry MacNeish as he owned an
original L/89 69 Chevelle. In every case, I found that
original L/89's used hardened steel washers under the head
bolts.

I can try to dig up that information for you. BTW, the
stock washers are still available from GM. If you think
about it logically, the washers keep the bolt seats from
getting badly marred during assembly.

Steve

[nuch_ss396]

Bob,

This is an excerpt on the L/89 head bolt & washer topic:

Re: Head bolts - L/89 equipped big blocks for 1969

Steve-----
GM parts has everything that you need and under the original part numbers:
1) long head bolts------GM #3877669
2) long head bolts------GM #3877668
3) washers--------------GM #3899696

These exact same washers were used for all 67-71 big blocks with aluminum heads. Chevrolet big block aluminum heads bolt seats were cut deeper by the thickness of the washers so that stock big block head bolts would still engage the same thread depth in the block.

The above-referenced head bolts are the original part numbers and conform to the original specs. However, the headmarkings on currently available bolts are slightly different than originals. On the originals, the ends of the "cross" on the bolt head extended all the way to the head perimeter. The "cross" ends on the current bolts are shorter.

Hope this helps Bob.

Steve

[Belair62]

Great info...I was thinking ARP stuff which this does not have. I assume the torque is stated for use with these stock washers too...65/75 ?

[nuch_ss396]

Bob,

I will have to re-check a GM service manual I have. I seem
to recall that the torque was less due to the washers.
I will verify this evening for you.
Steve

[nuch_ss396]

Bob,

This is what I used for torque reference. I hope this
helps you.

Steve



These are the torque specifications. See note #3 @ bottom.