The only two things wrong with a 248 are #1: There are two bigger engines and #2 No one makes pistons for them. Actually California Bill liked the 248 crank for a street engine because of it's shorter stroke and smaller ports. If the 248 will go out to 3 15/16 like the 270 you'd have about 278 CI. If you are not going to race it it'll be fine. I ran a 248 for a while in my '53.
