Can a 4" bore be achieved in the 250 block with good wall rigidity for everyday use, without cementing the cooling passages, if the cylinder wall castings are well centered, not having drifted during the block casting process? One of the other Chevy boards mentioned a minumum wall thickness of 0.250" on the two thrust side of the bore. An ultrasonic meter could be used to selectively screen the best blocks for maximum wall thickness.
The 4" bore would also all the use of one of the Chevy 327 pistons (not the OEM STD) with a 6" connecting rod.
