'64 French Locks

[Shane G.]

I have 2 sets of French Locks for the half shaft flanges - on one set the steel area between the bolt holes is curved and has a reinforcing rib pressed into it. On the other the steel area between the bolt holes is square, flat, and not as wide. Which of the two are a correct configuration for the 63-64? I am pretty sure the 63-64 are different than the 65 and up, but I have no idea which set to use.

[Joe L.]

Re: '64 French Locks

Shane-----

You're correct! A little-known fact is that the 63-64 u-joint flange bolt french locks were different than 65+. The 63-64 french locks were the flat, narrower variety. Originally, these were GM #3843385 which were discontinued from SERVICE in January, 1965 and replaced by the 65+ french locks, GM #3860543. The latter part, which has the reinforcing rib, remains available in SERVICE from GM to this very day. I wouldn't use them, though. For this part, stainless reproductions are the way to go.

[Joe L.]

Addendum

One thing that I forgot to note (I was thinking about it when I composed my previous post and then I forgot to include it): very late 1964s likely received the 65+ style french locks. I don't know exactly when the change actually took place, but I would say that it was likely about early spring of 1964. After that time, I think it's very likley that all 64s got the 65+ style french locks.

[Shane G.]

Thanks Joe *NM*