Our 37 pontiac project came with a chevy pickup 5 on 5 rear, the same bolt pattern as the pontiac and the 57 caddy eldo wheels on it. the Eldo wheels look a little too wide, we haven't done anything on the car since we got it 15 years ago, another not started project, It has some cancer in the bottoms of the doors and floors, so we just have been doing the easy ones. There is a wiki her on hotrodders about upgrading to later GM parts from the 50's and 60's but around here they are hard to find. I have looked on the Hamb at projects putting Jag XJS front suspension crosmembers in, gm cars from the 30's thru 50's. WE have 4 Jags susp on pallets, for more not started projects.