prepping for my first swap...again

[MDPotter]

Same as above - they are the same block. The pistons on the 5.3 are dished and 4.8 are flat.

Sounds like it should be a 5.3, but look at the pistons and you can tell.

A 4.8 isn't a bad engine, it doesn't make that much less power than a 5.3. No matter which engine it turns out to be, you could put a cam in it, a tune, intake, and exhaust and it will probably be plenty of power for you.