The bellhousing that you are using fits V-8 truck engines from 55-59 and 63-67 and 6 cyl engines from 63-67. It will accept any 3 speed, or 4 speed transmission of that era. The throughout arm is the same as the 235/261 6 cylinder engine/bellhousing used.
As 3B indicates, the differences in the clutch would be the diameter. The clutch disc splines would be the same as well.
Fred
