Just purchased a 1979 F150 for my granddaughter. It had been parked for a couple of years. It looks like the engine has been changed to a 1996 360. I bought it without seeing it run but I got it for a good price as it is pretty clean. My problem is that I cant get it to start. Here is what I narrowed it down to. I put one of those light testers you put between the distributor and the spark plug between the coil and the distributor and this is what I found. When I turn the key on to the start the starter comes on but no light on the tester, Instantly when I back the key off from the starter position the light comes on showing power to the distributor but it doesnt come on soon enough to take advantage of the starter. Then when I turn the key back toward the off position the light comes on briefly. So, I am not getting power to the distributor during the start mode. I put in a new ignition switch thinking that might be the problem but that wasnt it. I replaced the ignition control module, still no luck. I also put in a new starter solenoid and a new battery. Any Ideas????

 

96 didn't offer a 360.

Being a swap, Is it still using the stock electronic ignition?

 

I remember ballast resistor issues caused unusual symptoms as you describe but it was opposite as you describe. I would look at that circuit however. It would be nice to know if you still have the original Duraspark ignition or a system original (TFI) to the 96 engine. The engines available for 1996 were the 4.9 I6, 5.0 V8 or the 5.8 V8.

 

Some starting systems had an " I" terminal on the starter solenoid. The purpose was to provide full 12 volts to the Ign system on starting and then drop back to lesser voltage to the coil to prolong coil and component life. Might be a good idea to confirm that wire is there and not inadvertently discarded
Some systems had a coil that was designed to operate at 12 volts all the time while other coils were designed to require the Ballast resistor. Sometimes folks get into changing stuff without knowing how the system is/was designed to work and create all sorts of problems.