Out of curiosity, is the depth of the hole that the starter goes into the same between the 2 housings?
What I'm wondering is, will a starter from a late version with nose cone fit into or bottom out in the early housing with the bushing. Aside from the issues of the mounting bolt hole sizes and ring gears, just wondering on the depth.
No. The small frame starter bell housing (early) is 2 3/16" deep and the large frame starter bell housing (late) is 2 3/4" deep. This is measured on the bells only from their flat block mating surface to the spot where the nose or shaft would touch the back of the bell.
You're wasting your time trying to pop a late starter in an early bell. The only common ground between the early/late bells is the center of the hole distance between the two starter mounting bolts is 4 1/2".
The early steel plate hole is 3" and the late steel plate hole is 3 3/16".