I have a '52 F1 with the old flat head 8 with a 3 speed transmission currently using a 10" dia. clutch with an 1 3/8" spline.
Is it possible to go to an 11" clutch and if so, does it use the same bolt location as the pressure plate used on the 10".

 

Not an expert by any means but I think it might be doable. Matching pressure plate and all. I'm sure when the experts wake up one will let you know for sure.

 

On the 226, the bolt hole locations are different. I think you could have a shop drill your 10" flywheel though to take an 11".

 

Most people go the other way, from 11 to. 10. The 11 is a very heavy clutch. Why do you want the 11?

The holes are counter-bored a specific amount. It needs to be done precisely, as far as location.

 

My flywheel is drilled for both. It has a 10" clutch, but there are a second set of holes drilled and tapped for a 11" clutch.
'52 F1 C1BA/8RT.
...Terry

 

Way back, I used a pressure plate that was 1/2" larger than the clutch plate. If you ever look at a used clutch disc, you will see the outer edge is unused. By putting a bigger pressure plate, it uses the whole face of the clutch. So logic dictates that if you use the whole face you are getting better power.

Later!
Mr. Ed

 

what I would really like to do is go to a diaphram style pressure plate. But all I can find are clutches with 1 1/8" splines.
In addition the throw-out bearings seem to be different.
Trying to get away from the grabby 3 finger pressure plate...without re-inventing the wheel.

 

I tried the Y-block 10" diaphram, the fingers rubbed on the throw out collar. It was very smooth, but they were only used in Cars which used the smaller input spline. That's why you are seeing 1-1/8" splines.

 

well that solves that bad idea.
as always thanks for help.

 

Unless you're driving a dump truck, there's almost no need for the 11" clutch. It is exceptionally heavy. Most people try to help the old flathead rev up quicker by lightening the flywheel and ditching the 11" clutch in favor of the 10" or even the 9-1/4". There's a happy medium in there for a pickup...and your driving style/intended use.

 

thanks Ernie, appreciate your reply

 

Not necessarily. Flywheels must also dissipate heat via mass. If you increase the friction surface without increasing the mass then you can burn the clutch more easily.

Ross is right . . . Diaphragm clutches are normally not used in trucks. The finger type clutch (which is also adjustable) are generally more durable.

 

I'm kind of puzzled by this; commonly the full face of the flywheel is not used (same flywheel used with 9-1/2, 10, and 11 clutches), but always the full face of the disc. Sounds like a bad PP or non-flat flywheel if the disc doesn't have full contact.