I sometimes assume that some things should be done that is just normal stuff in doing a tune up and looking for a problems loose wires and so on, but have you checked the little ground wire inside the distributor. These will break and fray as the yrs of use. It may be broken or about to. This grounds and points plate to the dist. housing. Plus do you have the double vacuum advance. And by now i think you have replaced the condenser. You may have back track doing some of the stuff in the earlier post if you have not done. When the motor died did you try hot wiring it straight to the batt after your intermittent problems showed up?...
orich

 

Do you have the canister filter on your fuel pump? Once got some sediment in the filter canister would run for a few miles then would clog up the filter. Let it sit for a few minutes would start right up and do the same thing. Cleaned out the filter bowl and the problem was gone.

 

New coil may be bad...

 

Doubt the new coil is bad, but I've been wrong before.
I've hesitated checking the canister fuel filter cause the pump is providing a good stream of gas when running, which looks clean...no sediment/crap, carb filter is good, and I found no gunk in the carb when I rebuilt it.
I will go back and recheck wires from coil to dist. and inside the distributor today. Haven't changed the condensor caused it passed the test given in my Clymer's manual.
I did bypass the resistor wire twice yesterday with a wire from batt to coil pos terminal, but wasn't quite sure how to do that. First time I pulled the resistor wire at the coil, ran wire from that post to batt and jumped the starter across the soleniod...cranked good but wouldn't start. Second time I just ran wire from pos battery post to coil pos with resistor wire still connected and cranked it with the key...same deal, cranks but won't fire over and run.
Gonna check with Advance Auto for the resistor wire today, then change condensor, check fuel pump canister filter, recheck wires and reclean/reconnect ground wires. Oh yeah, I have the simple single vac distributor.
Hope to solve this soon, so keep the ideas coming...gotta have wheels to go to work if I get a job offer later this week...she who must be obeyed doesn't like sharing her premium Merc Montego...go figure.

 

I'd put the old coil back in, and see if you're suddenly back to the original problem- 10 minutes of running, then dying. then put the new coil in- if you've got intermittent spark, i think the new coil is bad.

since your 2nd test with the jumper didn't work, i think you've excluded the idea that the switch or the resistor wire is the issue- its the coil, or something between the coil and the spark plugs.

 

Gee this should now be ez to pin point as you bypassing your other wiring stuff. Maybe back when you did a tune-up and installed new condenser+ This has happen to I'd say hundreds of guys that were not paying close attention to detail. while installing point or the condenser, that the condenser wire would end up being moved to the side of the dist. housing thinking it would be out of the way where it ends up rubbing the insulation off when the vacuum advance move the points mounting plate and causing it to short off & on. Also the points ground strap jumper can be twisted in tight causing it to fray to just a few strands not have a good ground that will make it have a weak spark. Also if the coil is hooked up backwards will cause a the spark to be off color Org/white (not) blueish. This can happen when the resistor wire is not put on the + side of the coil but put on the negative terminal side. This reverses the polarity of the coil. Was wondering if you have a manual or auto choke?Also is there any vacuum control valves in the cooling system that would open once the motor warms up that control the or advance the timing? These are mostly use on later yr motors but are mostly use with the double vac-advance distributor's. Any way those will leak at the base of the plastic.. orich

 

OK Gents...drumroll please...ba-dump-bump (rimshot)...the winners of the Stalling Mystery sweepstakes are...Orich and Rustywheel. Who kept after me to check the basics under the dist. cap.
Started on the truck again this morning...pulled and replaced dicey old ground strap from intake manifold to firewall, cleaned connections on the battery to block ground strap. Checked for spark off the dist./coil wire with a helper, cleaned and redid the coil terminal connections and got steady spark there...checked voltage from the switch to the coil...good, checked voltage out of the coil tower...good. Hooked coil wire to dist. and checked for spark at a plug...intermittent, but there.
Pulled the dist. cap, checked black wire to points...good. Checked tiny ground strap...good/tight. Pulled the Duralast red wire condensor, inspected wire and connection...looked good. Dropped in the old Motorcraft grey wire condensor that I kept as a backup last time I tuned it up. Cranked it and it fired up and purrs, ran without fail for a good 25 minutes...during which I lubed the carb linkage, adjusted the curb idle and richened the air/fuel mix a little to steady the vac gauge.
Put the air cleaner and oil cap on, ran it on the highway and around town for about 25 minutes. No sputters, no stalls, and it's back to running so quiet at stops that you have to listen for the engine.
So way to go sweepstakes winners! I owe you a frosty one and a big thanks if we ever meet. Oh yeah...I did a hail mary touchdown throw with the red-wire condensor...into the neighbor's yard who always complains about my Lab peeing on his fencepost at the corner. It'll get what it deserves from his lawnmower...shreds and splinters.

 

right on! glad to hear you got it sorted.

 

LOL tossed it neighbors yard who always complains ... lol

 

Been there, done that. Mine failed on the way to the lake, pulling my boat. Run, sputter, die. Cool off, run, sputter, die. I left the condensor unhooked and it ran well enough to get home.

Put old one back on and PRESTO, it ran fine. Them lil things can create more headaches then you can imagine.

 

Speaking from experience, when you replace the coil, I'd also replace the coil to dist wire, points and condenser. all the ballast resistor will do is keep the points from burning up over time. Not having it will not affect performance for a few miles. also, be sure and check the wire that grounds the distributor - the black one. That one stumped me for quite awhile. They tend to corrode or come loose alot.

This sound EXACTLY like the problem I had!!!