I have a '97 vortec drivetrain in my truck although I have not started it yet. (I have the complete engine and trans) I am using the harness from the donor vehicle as is one other guy I know about on here. That being said there are a bunch of wires to eliminate and track down circuits all over the place to figure it all out. Painless would be the way to go if you have the money. Here is a link to the correct harness from
summit racing and a link of the same at
painless
You can run the 700R4 just fine but will need a lock up controller if you dont already have one.