spark probs...
 

79 5.0L basic.. well, a trik or 2.... but, bout as stock as ya can get...
ran 15.8 92 @ IRP a few years ago, but mostly rests now...has a spark prob... rums for bout 20 min & dies.. zero spark.. sit for 10., & its fires up lyke nuthin happened...may run anuthr hour or 2 minutes.. ya never know..did the coil swap thing, modules.. (twice) new ignition switch.. & no help...could it be the distrib?...the 2.8 had a bushing that would arc on the housing & cauz fits w spark.. but, these characteristics are quite different...

any ideas????

My first suggestion would be the ignition module, but you've replaced it twice already. Check, remove and clean all your engine and body grounds, you may have some corrosion there. Bad grounds can cause intermittent problems like yours as well. Post again with any results.

The car goes pretty good for a 79 BTW. The magazines best times with those cars were in the 16.8 - 17.0 range. Hope you get it running again soon!