C1 Clutch Question

[Christopher R.]

Trying to determine what clutch to install in my '62 with the right transmission but wrong flywheel. Rather not replace the flywheel now.

I'm about to replace the Muncie transmission in my '62 with the correct T10. Which means I'll need a new clutch assembly. The engine presently in this car is a 1974 built 350. I know the T10 requires a 10 spline clutch. But what about the clutch diameter? 10.4"? Or, 11"? (10 spline clutches come in both sizes.)

I don't know what clutch diameter is in there now, because it was installed so long ago. But I do know that the flywheel was not changed, and the bell housing is the correct-for-'62 553 casting. I believe this 1974 flywheel had an 11" clutch. Not sure if this flywheel also had holes for the 10.4" clutch.

1. Does anyone know for sure if the 1974 flywheel has provisions for both the 10.4" and 11" clutches?

2. If I can install either a 10.4" or 11" clutch, do I care which one I install? Does one contain any advantages over the other?

[Joe L.]

Re: C1 Clutch Question

Chris----

First of all, you may be able to use the same clutch that's in there now. Generally, I would not, though, unless the disc is in perfect condition which is unlikely. All 1963-70 Muncies used a 10 spline input which was configured the same as early T-10s. It's not clear to me if your Muncie came from the same source as your 1974 engine. If so, it will have the 26 spline input and you'll need to convert to a 10 spline disc. But, if it's a pre-71 Muncie, it should be a 10 spline input.

C1 Corvettes originally used a 14" flywheel in combination with a 10" clutch. I don't think that a clutch assembly much larger than a 10" will fit inside of an original C1 bellhousing which is, apparently, what you have. In fact, I didn't think that a later style flywheel, although of 14" OD, would work with a C1 bellhousing, but I may be incorrect on that.

I don't know, for sure, if the 1974 flywheel was dual-drilled for both 11" and 10-1/2" clutches. By that time SERVICE 14" flywheels were dual drilled, but I don't know if PRODUCTION flywheels were dual-drilled. So, I don't think that there's really any way to tell what's in there now without actually looking at it.

If I were you, I'd wait until I see what's in there now and, if necessary, replace with the same sized-components-----you know that size will work. I doubt that an 11" clutch will fit, but if that's what's in there, stick with that. For street use, I consider the 11" clutch to be the best.

[Dennis C.]

Re: C1 Clutch Question

The 10.4" disc and pressure plate will fit just fine. Dennis