427 Chevy Block 2 bolt vs 4 bolt

[Xplantdad]

Originally Posted by Vortecpro

I have run across this conversion a few times, and its always to pass a converted 2 bolt block off as a production 4 bolt block. Heres where they make their mistake, 4.250 bore two bolt blocks do not have the bores notched on the intake side, 4 bolt blocks do, and replicating the factory notches is not something these conversions have successfully been able to do at least when I examine them.

Mark is a wealth of information...and builds killer big blocks that make really good horsepower on pump gas.