I had the same problem in my 79 with a 400. My problem was that when I'd stop my truck I couldnt start it untill it cooled. One of those times I happen to have some water and I poured it on the ignition control box b/c It nearly burnt my hand when I touched it. After I cooled it off the truck fired right up. I bought on from AutoZone but eventually ran into the same problem...I bought my next one from Checker an its working great....I kept the old one as a spare...The symptom for my truck was that when I tried to start nothing would happen...
Been there before too. Go get a new ingition module from the auto parts store. Keep the old one in case of emergency. If your're junk yarding, keep an eye out for a spare. Just makt sure it has the same color gromet for compatability.
If you want a GOOD module find a Ford Motorcraft OEM module. Many parts stores have testing machines for igntion modules. When you mount your module use spacers to hold it 1/4" off the mounting surface. This will allow cooling air to get to the bottom of the module. Cary the parts store module as a spare. I run an OEM module now and I haven't had to change it for years. The parts store modules would run a year at best.
I had a similar problem, but it turned out not to be the module. I had a pinhole in the fuel line, back by the tank. I guess it was letting air in, and with the engine warm it was "vapor-locking" somehow. I had to manually shake the fuel line from beginning to end, until my grand-daughter saw the wet spot. Until then, I had changed modules, coils, etc, and as the engine had cooled off, it seemed fine. That is, until it got warm again. Just one more thing to check out.