What's the size of a 383 4 sp clutch in a 69 Cuda?

Oldmanmopar said
the way I always told was Cast iron bell 11" aluminum 10.5 . usually held true for me ? 1970 was the first year for aluminum BB bell 10.5

The stock bellhousing in my 64 Belvedere is cast iron and has a 10-1/2” flywheel. The 69 bellhousing that I sold earlier this year was cast iron and was for 11”.