Engine ID help?

[Xplantdad]

A friend of mine has a 56 Chevy and has a big block Chevy in it. He was told that it was a 454 but the air cleaner has 427 Turbo jet on it ( I saw the car briefly while I was in SoCal). I told him to get the "numbers" of of the front pad and that someone here could probably help on the ID.

So here goes...

Front: T0520CXS 14Z473787 (he said that the Z could be an S or a 5?)

Back driver side: 3999289

So what does he have under the hood? Can you tell what year, HP rating, what it was installed in originally? 2 or 4 bolt mains?

Thanks for any help