230 and 250 engines run the same block casting and cylinder head. The difference is the crankshaft stroke. Both have a 3 7/8" bore, same as a 283 V8. Pull a spark plug and stick a borescope into the cylinder. 230s have flat top pistons- - - -250s have a D-shaped recess in the piston crown about 1/4" deep. Pistons for a Chevy 307 V8 are a drop-in swap to raise the compression ratio of a 250 six.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!