2001 vs 2003
 

I have a 2001 Silverado 2500 5.3L 4x4 (6-bolt wheels) that's pretty rosted out, but a good drive line with only 130'000 miles on it. I also have a 2003 2500HD (8-bolt wheels) rolling chassis and cab with no engine, tranny or transfer case.

Would lifting the driveline out and putting it into the 2003 be a good idea? What would the problems be? (Electrical, computers, boxes, imobilizer etc)

Edit: The 2003 used to be a 6.0L while the vehicle I'm taking the engine from is a 5.3, will this be a problem?

Found the biggest problem online (maybe it can help someone in the future): Up to 2001 they are "drive by cable", after 2002 they have an electronic throttle so you need the throttle-body (maybe the whole intake), boxes and gas-pedal from the car. And putting an older engine in a newer car is maybee a little stupid?:p

I will keep my old truck, with engine, but use the rolling chassis for parts, and maybee use the 8-bolt axles and suspension from it. Then sell the frame and cab to someone who needs those parts.