On the front of the block, in the recessed area to the right and below the water pump holes. If you have an accessory bracket installed, it will prevent you from seeing it.

 

10-4 simple enough to pull off, thanks

 

Actually the advice above to look for the 4.8/5.3 or 6.0 on the front of the block is better advice for what info you need.

 

I was pretty positive it was a 5.3, the only reason I questioned it now is because someone above listed that the pistons were a 6.0, I wanted to verify what generation I had because It was supposed to be a gen 3 5.3 with gen 4 pistons and rods but they obviously aren't gen 4 pistons