Here's the issue: I have a 1969 Mach 1 with a 1970 351c motor that starts and runs fine for about 15 minutes then stalls. Once it stalls, there is no spark from the coil wire to the top of the dizzy. Cools off, and starts right back up with the same pattern of stalling. When it stalls, still gets 12v to + side of coil (Accel, less than a year old) (I replaced the resistor wire from the ignition switch with a regular wire). I have a replacement coil, and both coils get the same result. I removed the quick connect to the dizzy and direct wired it after the problem started, thinking it could be the problem, no luck. The dizzy is less than a year old. Any suggestions other than replacing the dizzy again?

Newer parts:
Accel Coil and distributor (electronic ignition)
Ignition switch

 

You have the incorrect voltage on the coil. Coils only start on 12 volts, but they run on 6-8 volts. There is a resistor wire from the ignition switch, which drops the voltage. The starter solenoid has a second connection on it which jumps this wire for starting (as long as the solenoid is active). This provides a hotter spark for starting but the coil will not tolerate this high (12Volts) voltage for very long. Someone has replaced the resistor wire and is ruining your coils. For some reason I can't add an attachment, but if you look at the wire diagram you will see that the typically pink wire from the start pin (C) on the starter switch is a resistance wire. It may have a net type thermal insulator around it. Make sure it is there and connected correctly before you ruin another coil.

 

The resistor wire is still in place. To clarify my earlier comment, I jumped the coil directly from the battery to see if it would start, to confirm it was not the resistor wire. I'm pretty certain the coil and resistor wire are not the issue. Any additional thoughts would be appreciated.