wiring harness

two steps forward, one step back. I had my 68 440 barracuda ready for paint[hot rod flat black] and thought I would take is around the block one more time before delivering it to the paint shop. With the engine running, I slammed the hood and smoke poured out from under the hood. An unfused electric fuel pump[not installed by me] smoked its 14 ga feed and damaged the main feed from the firewall, the ignition plug, firewall block and maybe more. Question, does anyone have experience with aftermarket wiring harnesses? Would I be better repairing the old one? I dont mind spending the money if it prevents a car fire!