400 B block
the 400 block is a start to a build. girdles are pretty much a waste of time in my opinion though. the 230 casting 400 block i think has the largest main webbing but 74 and under blocks will work fine. my engine is a 500ci 400 block with billet side bolt mains and alittle hard block in the water jackets. I used nice parts and spent ALOT of time on the cylinder heads and with an 825cfm carb, solid flat cam and 93 octane shell gas it made over 685 with almost as much torque with the nicest flatest curve i could ask for. Its average hp and tq is over 600 all the time from 4200 to 6400