The motor says 4.8 on the back but I've seen some that have 4.8 6.0 on the back.The motor is a long block and has aluminum heads.I can pick it up for very cheap so it doesn't really matter what it is,because im going to buy it anyway.

 

4.8 and 5.3 are same block . if it says 48 its not a 6.0

 

The back of the block should have "4.8/5.3" stamped on it. There isn't really a good way to tell the difference between the two with the heads on. The 4.8 has flat top pistons, and the 5.3 has dished pistons.

What's your plans for the motor? How cheap can you get it? If you starting from a bare block, why not start w/ a 6.0L and get more cubes and better heads?

 

Maybe the head gasket .. there should be some tabs sticking out on the side, around center of the heads. On the tab should be stamped the displacement. 4.8 and 5.3 uses a different head gasket I think, so you should be able to tell by that. Otherwise you will have to pull a head and look at the pistons.

 

The heads on a 6.0 have 317 on them I forgot what 4.8/5.3 heads have.