I have a 57 super 88 but i don't know what size the engine is.Are the casting #'s on the back of block ?And where can i look up that the casting number guide?I think the motor is original,it has like a air gap thing on the intake.Somebody said it might be a 371 but the motor doesn't look that big.

 

Not too sure about anything older than '68, but the casting numbers could be just behind the timing chain and before the manifold in that little valley