Wheelnut unless you plan on digging inside a 230 and a 250 and randomly swapping parts everything that bolts onto the block is the same. Internally for the same production year they share the same bearings, timing gears, gaskets, oil pump and screen, push rods,lifters, and rocker arms, and connecting rods. After the base short block is together with the correct parts inside it, everything else that has to be attached to complete the engine can be changed from a 230 to a 250 including gaskets. There were a few different chamber sizes on the heads but that was only to adjust compression ratios slightly for emissions and so on. The one big exception is the 194 head with the small chambers and that bolts right on too; but since you don't have one don't worry about it.
Mike G
