wiring probs

[Xzavior240]

I recently came across a 72 chevy half ton that I decided to restore. The previous owner hooked something up backwards and completely fried the wiring on the engine when it was rewired there was no ignition what so ever not even a click when you turn the key. Can someone pleaseeee!!!!!!! refer me to a place where there is a wiring diagram that covers this truck or possibly send me a copy if they have one? it would be greatly appreciated. I have the wiring for the lights hooked up which I aquired from a broken down 79 with similar wires. as for the rest of the diagrams Im clueless as to where to even start to look for it . Thank You .