i recently bought a 74 roadrunner with a 440 Non original , and was running and driving when I got it. I took it for a spin and the engine wiring harness was not secured and the wires to the alternator melted on the valve cover. I ended up thinking I was better off buying a whole new clean wiring harness for classic industries for a 74 with a 400/440. I installed the harness and now the car won’t start. I checked every connection and compared it to a diagram. When I turn the key it cranks for about one second and then does nothing. I can start it at the relay though by jumping it with a screw driver though. I checked relay, ballast, and the ignition in the street in column and all work. The only thing I can think of is that the new harness never came with a connection for the seat belt interlock device. The only one had one connected there but it was moded (both yellow wires cut and jumped). Perhaps the harness was oem and didn’t already come with the jumped wires? It’s just weird that it will crank for one second and then completely stop and do nothing. I may just use the old harness and repair the wires that got melted and shorted if I have to. Any help would be appreciated.