Is this a 5.3 or 4.8

[jomo]

not on the trucks the pcm changed in 03 and that was the beggining of the ETB trucks

Well the throttle body is drive by wire and the pcm is 12200411 and upon a search they said its 2001-2002. Lets just call it a 2002 engine. It does not matter its going in a 50 plus year old truck.lol