Blasted computer- - - - -it eats a post occasionally! Unless you can decode the stamped number on the machined pad by the distributor, it will be hard to tell. Both 230 and 250 engines use the same block casting, and the cylinder heads are also the same. The reason for the dish-top pistons on the 250 is to keep the compression ratio the same on the larger engine. About one full ratio of compression increase can be had by installing flat-top pistons for a Chevy 307 V8. The bore size, compression height, wrist pin size, and weight of the 307 piston is the same as the 250 piston. With a slightly hotter camshaft and the compression increase, the 250 gets pretty perky!
Jerry
