Try running a temporary ignition switch circuit- - - -a toggle switch that bypasses the ignition switch and wiring, straight from the battery cable at the starter- - -into the cab- - - -and back out to the coil + terminal. That will eliminate any potential primary wiring problems and focus attention on the coil and distributor wiring. That cuts your diagnosis area at least in half.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!