SB or BB a body debate

It's pretty simple, the short stroke B engine will turn some serious RPM with even stock parts and the right cam. Good parts and proper build you have yourself an motor that will spin 8k and like it. A lot of other advantages too. Distributor in front, external oil pump, water pump easier to service, have a better intake set up with no hot oil on the bottom of the manifold, can change cams and pull lifters without removing intake. I would say a 400 B engine with an overbore and you will be at 408 power level. Good heads and you will make more power as you can turn a lot more rpm with the short stroke and stil have good engine life.