Originally Posted by selil
Here's a bit of trivia. GM has used basically the same bolt pattern for the bell housing for EVERY V8 (small block) and V6 since something like 1958? It's the standard pattern and Cummings diesels (4bt) use that pattern for their adapter plate in the Frito Lay and Wonder Bread box vans.
It would be 1955, and its small block, big block, 90 degree v6(200,229,265), as well as L6 and L4 pushrod engines but not the "W" motors(348, 409) or the 60 degree v6s(2.8,3.1,3.4,3.5,3.9,these share the small bellhousing pattern with the likes of the 3.8 buick and the northstar)