230 and 250 engines run the same engine block and bore size- - - -the only difference is the crankshaft stroke. Flat top pistons for a Chevy 307 V8 are a direct swap for 250 pistons- - - -the only difference is that the V8 piston is a flat top. It gains about 1/2 a compression ratio over the 250 dish top piston, and there are both hypereutectic cast pistons and forged 307 pistons available without ordering expensive custom made ones. Good luck!
Jerry