[streetbully]

Big block Chevy 572/620 Crate #'s on engine block

I just bought a 572/620 engine brand new (still crated) from GM a few months back and the number on the block is 24502506 after the last number (the 6) it looks like there is the letter B or maybe its an 8 I'm not sure. Is this a truck block? It actually comes up on google as a 454 block, it this correct? Thanks for any help.

 

[BowTiePride]

Not entirely sure, I'm an SBC guy, but it could just be a 454 block stroked and bored. But then again it's just a shot in the dark. If you bought a 572 from GM, it's a 572. No way they'd bend you over, unless it's not from GM...

 

[cobalt327]

I just bought a 572/620 engine brand new from GM a few months back and the number on the block is 24502506 after the last number (the 6) it looks like there is the letter B or maybe its an 8 I'm not sure. Is this a truck block? It actually comes up on google as a 454 block, it this correct? Thanks for any help. Please e-mail me @ [email protected]

Your engine (if genuine) is based on a tall deck block, so it's in the same "family" as the BBC "truck" engines, but yours is a far cry from a traditional 427 truck (tall) block. The bore is larger (4.560") than on a 454, as well. It has siamesed bores and a 1-piece rear main seal.

It's easy to tell a tall deck block from a standard deck block, tall blocks are .4" taller than the standard block, so there's more distance above the water pump outlets in the front of the block.

 

[streetbully]

572/620 casting numbers

Thanks guys figured it out. I call GM Performance Parts in Michigan and in fact casting # 24502506 is a 572/620 tall deck race block also used on 454's.