1974 exhaust manifold french locks

[Rick M.]

Have a couple projects going on and one of them is rebuilding a 74 L82 engine. There is a thread over at Corvette Forum on it. When I tore the motor down, tossed all the hardware in a box. Now looking at the parts, see the exhaust manifold locks are 2 different styles of ears. Squared and rounded. Anything can happen over 50 years, but, manifolds appeared to have been original to the motor and never removed. Was/is it common to have both squared and rounded ear locks in 1974 or was one likely replaced at some point?
IMG_3898.jpg

[Joe L.]

Have a couple projects going on and one of them is rebuilding a 74 L82 engine. There is a thread over at Corvette Forum on it. When I tore the motor down, tossed all the hardware in a box. Now looking at the parts, see the exhaust manifold locks are 2 different styles of ears. Squared and rounded. Anything can happen over 50 years, but, manifolds appeared to have been original to the motor and never removed. Was/is it common to have both squared and rounded ear locks in 1974 or was one likely replaced at some point?
IMG_3898.jpg

Rick------


The french lock which appears in the upper of the photo is a GM #3880844. This is the french lock originally used on 1966-82 small blocks.

The french lock which appears in the lower of the photo is a GM #12338135, once upon a time available in SERVICE. It did not even exist in 1974 so this must be a replacement that occurred somewhere along the line.

The 3880844 and 12338135 were replaced by the GM #14011241. The 14081241 was identical to the 3880844 except that it had three very small indents equally spaced along the curved section. It has also been discontinued without supercession.

One caveat: GM was using these french locks by the millions in the 60's and 70's so it's possible that there were multiple suppliers, one or more of which may have made the 3880844 with the rounded tabs. I doubt it but it is a possibility.

My choice: for these french locks I prefer stainless steel reproductions of the 3880844. I hate rust.