Funny that no one ever mentioned staying away from 400/4 bolt main SBC. Not a good setup at all. There is not enough meat around the main bearings to keep it together at higher RPMs. Two bolt FTW.
400 SBC’s are great motors. I loved mine & NEVER had cooling problems with it. Put alot of abusive miles on it, too. It was in a G-body with a T5 5 speed & 9 inch ford rear with 3.89s in it. That car was a blast.