A few times lately that I've had my 1970 'Cuda out the engine will just randomly shut off just driving down the highway. No sputtering, just engine off like I cut the ignition. I coast to a stop, look under the hood and see nothing disconnected. I get in and turn the key and the car starts and runs perfectly. This has happened a few times. I hate not being able to trust the car. I have the Mopar Performance electronic ignition, no orange box, I have one of Ehrenberg's black boxes that is sold on ebay. Seems fine, good ground etc... Could this be a faulty coil?

a bad coil will do that !

Sounds like a connection is getting hot and going open, commonly refer to as a high joint in electrical trouble shooting.
It could be in the ignition switch, the wiring in the steering column or in the instrument wiring harness to the bulkhead connection or in the engine harness under the hood
Do you jiggle or touch and move any of the wiring when it quits? If so try doing only one thing only at a time until you can figure out exactly which circuit or wire is causing your troubles
Good luck
Please let us know what you find

PickUp coil in distributor will do that.
Had happen to me once as you described.
Seems after it gets hot losses continuity internally.
Cools a little then makes contact again..

had one years ago that would die when one closed the R door, but start right back up. Drove the owner nuts .
What I found was one of the female receptacles in the control box connector was not positioned properly when it was molded so the receptacle was too far in and barely touching the male pin. Replaced the harness/ connector and EOP

I have also seen ballast resistors go open when they get hot enough and reconnect after cooling. likely not the issue but they are cheap and good to carry a spare.

Another was a bad coil wire that the conductor was burnt a good distance into the insulation from arcing on one end.

Another yet was an internally broken wire on the pickup lead likely caused from years of flexing with the vacuum advance movement.

Fun ones to find and All simple things to check that are sometimes overlooked. Keep us posted

Way back at the Dawn Of Time, a buddy with a '70 440+6 GTX had that going on.
Drove us nuts until we found the distributor wire had a bare spot and would occasionally ground itself on the housing.

Distributor pick up. Box would be second choice.

I too had the same exact frustrating problem. I substituted the ecu, distributor, coil, and ballast. Thought I had it fixed then it happened again months later while warming the engine up. My problem was a loose wire at the crimp in the spade connector to the ballast resistor.

Had this happen to me. Car just shut off. It restarted and I got home. When getting out, my foot brushed against the ignition switch connector at the base of the steering column. The engine hiccupped. I grabbed the connector and gave it a jiggle and the car died. It was just sheer luck that I found it that quickly. Check all your connections.

If it has a factory amp meter - check the two wires at the gauge for tightness.

Bulkhead connector when it happened to me.

Start it up & jiggle the wires that connect to the ballast resistor. I'll bet they will spark & the engine will die. Then it will start right back up. If so, replace the $2.00 ballast resistor. I went through this back in the early 80's with my old '71 Hemi Charger. I went through a long list of other things before I discovered this!

This is a follow up on my original post. The problem turned out to be the Ignition Control Module. I changed it out having exhausted every other possibility. I had it mounted under the battery tray, an area with plenty of ventilation. It was well grounded.
I drove the car 3 days in a row. Never a hiccup. Starts easier too. I had an NOS Orange box, made in the USA stamped on it. Maybe it will last longer. This is a nice car. Original 440 car. Had it since 1979.

Looks Beautiful

Thanx for the resolution , I had one of his Chinese Hi Rev 7500 Ignition Module do the same

Also had a ignition coil from OReillys , MasterPro fail when getting hot at idle running an factory 1.2 OHM Ballast

Hit and miss with all this Chinese Junk

That's a really beautiful looking Cuda!!! Glad you found the issue. Your NOS controller should last a long time too.

thanks for the follow up.
Just cause I'm a type the only way to be a 100% sure the box is bad is to reinstall it and see IF the problem returns. Sorry but my years in R&D required back to back testing (sometimes more than once) to confirm results especially for the German VP I reported to.
however there was a problem with a Autometer digital pot scrubbing speedometer that would not calibrate several years back that we chased for 50 hours (or more). I even had a sillyscope on the signal. We did what your not supposed to and changed 3 or 4 things at once and it magically started working. UHH I didn't backtrack on that one