Don't let these guys spook ya. You have something that is worth a few bucks. It's been sitting so it would have to be gone through and some new gaskets but for a markIV 454 4 bolt and rec heads has to be worth 8 to a grand as it sits. But the only way you will know if it is worth more is you would have to see what pistons and crank and such are inside.

That could be an LS 6. I remember going to a local chevy dealer back in the day and they had several of them lined up in the parts department in crates. They were painted black like that and had a sticker on the crates that said not intended for marine use. They were 11:1 compression. They had aluminum intakes on them though.

You have officially passed casting number relevance , look and see if you can find the numbers on the deck surface .may have a real contender there .

There should be a stamping directly above the timing cover and between the two top bolts (in the pic, it's the area that looks like the painter missed). The intended service of the engine can be deciphered from the stamping. Can you take a picture of that stamping?

LS5 would be oval port, thinking like someone else stated there should be a number stamped in the deck surface of the block in front of the right head.

If the first 3 letters stamped on the front pad are "XCH" I'm interested in it.

There were different flavors of the low compression version of the chevelle ss454 motor, for crate motor duty, from what i remember , some were very special.but all that info is going to be stamped on the deck of the block there

if you can borrow a bore scope and get a pic of a piston top thru spark plug hole, a lot can be told by that.

You guys see this story about what was found in a GM crate recently ?
Chevrolet 427 ZL-1 Engine Block Found New in Crate Stored For 40 Years
http://www.msn.com/en-us/autos/enthu...AmMILm#image=1

so that,s where i left it,hope they send it back to me.