Difference between 2 bolt and 4 bolt?

[robber6910]

What is the difference between a 2 bolt and 4 bolt main? How do they perform different from each other? I have heard that 2 bolts are not a good engine. All opinions are deeply appreciated. Thanks

Rob

[moparts]

probally not any performance difference just stronger. have built and run both and also have run and blown up both. hope that helps

[Daytona Yellow 69 Z28]

A 2 bolt main has only 2 bolts per main cap, and a 4 bolt main has 4 bolt per main cap.

[CDAUSA]

Bout a thousand $$ in places---more if it is the right 4 bolt. Some controversy on the 2 vs 4 bolt blocks. The caps are larger on the 2 bolt so some say they are stronger, but 4 bolts have.....well 4 bolts.

If the caps are tight in the block, running a cross drilled crank, and a straight bore....I don't know how you hurt a bottom end in a Big Block Chevrolet if it is put together right!!

[x44d80]

about 15 years ago a racer I knew ran in the 10's in his 66 chevelle with a 2 bolt chev block and 3/8's rods. I'm sure the engine was put together well though.