Hi all, as the title says what year of blocks are the best for building a drag motor for 355 or 383? We have a 327 in our drag car right now and are wanting a combination with more torque. Right now we have a 4 bolt main block which my dad believes is from the mid 70's but I haven't checked to see what the casting numbers are. We also have another 350 block thats just 2 bolt main.

I was wondering what the best casting numbers were to be more dependable for 500-600hp n/a'd drag motor w/o nitrous. Thanks!