Wiring a vortec engine

[tbrown5079]

OK, I have a 4.8 vortec from a 2007 GMC pickup, with the computer and transmission from the donor vehicle. The engine harness was reconfigured for my 56 pickup. The fuel injection is still on the engine. It is a simple wiring harness with 12 circuits and the GM color codes. All the wires are marked, but for a sbc with a distributer. There are 3 wires in the engine harness that need 12v with the key on. Do I use the wire in the main harness for the coil ( which I don't need ) to put 12v to the 3 wires?