I had a friend that built a mid eighties cutlas and put a old 500 cube caddy motor in it.
He called it the cutlac...lol
It ran 720's 1/8 . Stock motor with a performer intake, holley carb homemade headers as the only upgrades, that thing had to be making around 500 plus ft pounds torque or more and he ran a welded up 7.5 rearend and a 200R4 trans, ran it that way for four seasons without a single failure. I couldn't believe it.