FWIW, I installed a new harness in my 48 F68 (F-3), and couldn't get enough power to my coil to run the engine, after changing a lot of parts I finally traced the problem down to the yellow wire under the dash that was suppose to run power to the coil from the ignition switch ran out of the harness as the fuel sender wire and vice versa-(both were color coded yellow)- ie my fuel sender wire was the coil wire and the coil wire was going to my fuel guage. So after running through the fuel guage the wire to the coil had 6V, but no amps to make things work, what a PITA, but I got them swapped and everthing works great now. Moral of the story, cant always count on new parts to be correct and double check everything.