[Srubydo1986]

How integrated were the fuel injection setups in these trucks ?

As far as i know they'er pretty interchangable as as it with a couple of years.

I already have an engine that runs great with it's carburetor and intake. It would cost too much to make the TBI setup produce the same amount of power so I do not want to deal with it.

Actually a tbi setup will give you ore power and better response in the petal. It may also help in fuel economy.

Is the wiring harness for the fuel injection easily removable ?

Youll have to get a truck with tbi and take it computer and all. I removed every thing tbi from my jimmy and made it carb. setup If your good with ur hands and make every thing before removing and remember to takes picture i dont see why it would be to hard to change over.

What is the difference in the fuel system as far as the pump (mechanical? electrical?) and is there a return line ?

The pump is electrical its in the tank ull run wires to that but ull get that from the donor truck as well. IM Not positive on a return line dont quite remember that hopefully someone chims in for that one. All the fuel line are metal cant use rubber on that set up or at least mine didnt.

Hope this helps