Hey Fern,
I think what you have is 10 3/4" clutch.
I bought one this past summer for my '52 3600. It was USA made.
Click hereI just remeasured the clutch and your right, I actually have a 10 3/4" clutch.
I have already had the flywheel machined so I am definitely going to stick with it. I will pick up that clutch from Autozone, but they don't seem to list the pressure plate. Any ideas where I can pick one up?
I have a feeling this old one isn't usable:
Pressure Plate