Originally Posted by 302/Z28
First off, not all 283 blocks can take a 4" bore. The block needs to be sonic checked to see if it can go that far. A 327 requires a 3.25" stroke crank as opposed to the 283 and 302's 3" stroke crank. If you are after a 302 you would be much better off using a 350 block.
There is not that much of a performance differance in boring the 283 .060" as opposed to .125". The .060" bore with the 283 crank will produce a 292 and will allow enough cylinder wall material to remain.
To put a small journal crank in a 350 block would require special main bearings.