Perfect Charley. Interesting that they were not using flanged exhaust bolts.

Rick:

Isn't it SOP to have a washer under the bolt for aluminum engine parts to prevent galling when tightened?

Exactly why I was asking.

That seems to vary sometimes. Not to steer off subject but when it comes to aluminum intakes, I think the BBC used washers under the bolts from originals I've seen, but some SBC aluminum intakes didn't.
I know the 69Z's did not use washers under the bolts on the intakes.

Doesn't really make a lot of sense but that's what I've observed. Different assembly plants I know, but bolts gulling up aluminum you would think would want washers as kind of a standard procedure across the board.

https://i.postimg.cc/Wzd6cC2L/0.jpg

Rick: when did Chevrolet stop this method of attaching the exhaust headers to the heads?

That is correct, the BB engines (at least in 69/70 used a washer headed bolt other than where the engine lift bracket was bolted to just like in Charley's photo.

Please don't quote me as I do not study the early cars but I think possibly 1966?

Rick, do you know if washers under head bolts is also correct for L89 Corvettes? I don't recall if our car had them? I'll need to study up on the NCRS manual too

Dan

Based on the little research that I have done for this L89 I would say yes, they should have washers and would assume an L88 would as well.