Stopsign32v

I've never been a truck person at all but looking to move to the coast and get some boats so looks like I need to be a truck guy now. Looking into the differences of a 1500 and 2500 now. These things are confusing I tell you. Oh and I kinda want to mod it to go fast. Maybe a cam, longtubes, who knows.

Ideally I would like a 6.0 with 4WD. How can you tell if it is a 4.8, 5.3, or 6.0?