C2 Clutch fork rod length

[Ron Still]

Can somebody please confirm what the correct length is for the clutch rod that goes from the fork to the cross shaft for a 1966 with 327?? Is it 9" or 10-1/2"?? I ordered a new rod from LICS and the one I received is 9" and the one on the car is 10-1/2". Richard from LICS is quite certain that the 9" is correct. The car has been "in the family" since 1968 and nobody can recall this ever being replaced. Also, Richard said different X-Shafts are used with different length rods. I called a local guy in town who also owns a 66 with 327 and his IS 9", so now I'm really confused! Did they use different parts depending on production dates? Any help solving my mystery will be appreciated.

Ron

[Gary B.]

C2 Clutch fork rod length

Ron,

There is something on this topic in the archives that I think Joe Lucia contributed to. I think the current GM service replacement rod is shorter than the original rod and in some cases this will result in inadequate clutch adjustment. I think the longer rod is the original one, but check the archives for details.

Gary

[Joe L.]

Re: C2 Clutch fork rod length

Ron-----

LICS is correct about the fact that the cross shaft and clutch fork push rod were used as "sets". 1966 is a confusing year for these parts. According to some GM information, the 8-1/2" (not 9") pushrod (GM #3872960) was used in conjunction with cross shaft GM #3872962 for 1966 big blocks and the 10-9/16" pushrod (GM #3844209) used in conjunction with cross shaft GM #3832857 for all 1966 small blocks.

Other GM information indicates that the GM #3872960 pushrod (8-1/2") and GM #3872962 was used after early 1966 (probably cars built after about October, 1966) for all 1966 Corvette applications.

So, which is it? I don't know, for sure. However, I strongly suspect that if your car has a 10-9/16" pushrod and the clutch works with it, then you need the 10-9/16" pushrod as a replacement. I don't think that the 8-1/2" pushrod will work for you, at all.

Part of the problem here is that it's so difficult to identify which cross shaft you have in the car. These cross shafts were never identified by GM with a permanently applied part number. The differences between them involve a relatively subtle difference in the angularity between the lever arms. So, it's very difficult to "eyeball" them and ID them, especially with the shaft mounted on the car.

So, the easy thing to say is that if you took off a 10-9/16" pushrod and the clutch mechanism worked and adjusted properly with it, that's the one you need for replacement. Period.

By the way, both of the pushrods mentioned above are still available from GM for about 16 bucks, GM list.

[Phil P.]

Re: C2 Clutch fork rod length

joe---you have hit on a problmatic issue with most gm/chevy clutch issues that plague all of us when we are trying to do the "right" thing with clutch issues---the hot rodders know how to fix these problems,but it would be nice to have the members of this board check clocking on the "Z" bar and rod length to establish what will work regardless of what the factory called out---personally i can make it work, but it would help others to set a standard as far as "deminsions" are concerened to get it close the first time around---,phil

[Ron Still]

Re: C2 Clutch fork rod length

Joe,
Thanks for the great explanation. Richard (LICS) did call me back and offered to swap rods since they stock both. Sure is amazing what you can get into when changing a simple part like a linkage rod! That's part of the fun with these cars though. I never even thought about checking availability with GM.

Thanks again!

Ron