I think the 2947 clutch should work with all small blocks. That’s why Hayden began to manufacture them strictly for small block Mopars to fit the thicker radiators...specifically 2 row 1.25” resulting in a 3” thick unit...ie coldcase. At least from what I’ve read on other forums as well as here. That’s one of the reasons I decided to go that way as I didn’t want to run an electric fan. If I had to go to a direct drive fan I would have.
