my 5.3/4l60e swap is nearing completion, and I happen to have a 5.3 sitting in my shed that is complete, along with an LS1. between these 2 motors, which is going to be cheaper to make 400hp and be strong enough to tow with? My truck is nothing more than a towing vehicle, but I want it to be able to tow anything I throw at it. I plan on rebuilding the motor with fresh bearings all around, new rings, and probably all the gaskets. Here is a run down of what it is:

1994 GMC 1500 ext cab long bed
2002 Silverado 5.3/4L60E put into it
stock 2002 intake, intake piping, radiator, aux trans cooler, p/s cooler
It will be getting a set of longtubes as well, in the future.

I am interested to hear about cams, and if I need a stall or not. Chances are that the most it will ever tow is 6000lbs total including the trailer. Obviously in a truck this size, it wont be spinning very high, so I would like to keep the cam to 6000rpm or less, but I want it to make a load of torque down low.

I know the LS1 makes more power initially, so maybe I can swap parts between the LS1 and the 5.3 to get closer to that 400hp mark? I know certain 5.3 heads have smaller combustion chambers, which would bump the compression up a bit.

I have HPT Pro, so the tune is no problem.