1985 Chevrolet Truck tbi

It's doubtful you'll ever get this to work. I don't understand what you're asking, but you're swapping a few parts of a whole system. What about the electric fuel pump in the tank? What about the Check Engine light on the dash? What about the anti-theft circuit in the steering column that tells the Engine Computer it's okay to let the engine run?

Ok.. I found a harness that has been stripped down. . Was going to use my ecm or of my roadmaster but the ecm has a manifold temp plug. .. will it work without it. .. if not ill have to find a diff ecm.

You're on your own with this one. You're trying to do something no professional would attempt. You might consider looking for an aftermarket kit made for your truck. A friend tried to install one of those on his Suburban a few years ago. It did run the engine but he never did get it to idle at the right speed. He gave up and sold it "as is" a few months later.