72 demon 340 common under dash wiring issue for no start, no power

So i just installed bigger jets to accommodate for larger headers and when i went to start it up nothing, no lights, no cranking, nothing. I checked my battery voltage it was good, gave everything a quick visual and nothing jumped out. Threw a jump station on and just kind of left it on after trying to start it, still dead. Got under the dash and started moving around a couple of the main wire harnesses by the steering column. Just for the hell of it i pulled out the headlight switch and had head lights after i did the moving so i tried starting it and it fired up. Drove it for awhile came home turned it off and fired it back up a few more times no problem. I'd feel a lot better if i plugged something in or did something that i could actually tell made a difference .is there something common i should be looking for under the dash?

Its has a new battery, new starter, neutral safety switch.