I bought a of fe parts from a guy tryn to clean out his garage , I bought what he said was a 390
Well, on the positive side....he didn't lie to you
There are plenty of guys who would try to pass off a 390 block as a 428 based on "the numbers". If you were using Steve Christs book, forget about the part numbers in it. Most of them are useless.
It can be nearly impossible to determine a 428 block by looking at it. Except for early 332, 352 and 390 blocks which use the earlier cam thrust set-up, all FEs pretty much look alike, or can look different even within the same CID engine. They can be all over the place with different casting molds used. Like Kevin said, beyond the rear A or C scratches, which not all of them had, it would take some serious investigative skills to determine bore diameter and cylinder wall thickness to determine what it actually is....or what it COULD be.