I did however pull the engine harness today and noticed that the plug on the fusable link was not seated all the way. My guess is the dash side '71 harness is pulled out just that far too and made good enough contact to start. I think the '68 harness isn't pulled out and made good enough contact to run things like air but not good enough to crank. Just a theory though. I am going to go through the '71 engine harness and see if at a previous time someone re routed wires.
The ballast resister was also warm to the touch today in run.