427 Chevy Block 2 bolt vs 4 bolt

[big gear head]

It's not worth the effort for a street engine. I have a friend who is running a 396 in a B/S '69 Camaro running high 9s at over 8000 RPMs with a 2 bolt main block. If you can find a good 2 bolt block then it's going to be more than good enough for a very strong street/strip car. Too much machine work involved in installing 4 bolt caps on a 2 bolt block. After you get the caps installed you have to get the block line bored. If the rear cap doesn't fit just right you may have problems with the seal and thrust surfaces.

[Too Many Projects]

As Freddie said, a 2 bolt block is fine for street use. Find a 2 bolt 512 cast block and they are the same as the 4 bolt. I bought Freddie's 427/390 engine last year for just this purpose. It is standard bore and with a forged crank. The cast cranks and low performance rods were the main reason 2 bolt engines blew up at high rpm, not any fault of the block. Build the internals properly with a 2 bolt and you won't have any issues.