The MC head will work on a stock block. But i'm pretty sure you need a min bore of 4.500. (which i guess rules out a stock block)I also think the MC's need pistons cut a bit different than the original B-1's.

The only B1 heads i have right now are the ones on our 636 engine which are the B1-TS heads. Although i think the B1 heads are the best out there for choice and quality