Ok.... pulled tranny out of my '69 Bee for rebuild. While it was out I freshened up my 383's gaskets/seals/valley pan. Installed new plugs/wires. I put on new Chrome Powermaster alt.

Car will start. It runs for about 1 minute then shuts off like it immediately lost fire/spark. It will not start after that. Go out the next day and it will start but same dying and refusal to start.

I thought maybe something with new alternator was kicking in and killing circuit??? Put my old alternator back on and same thing. Dies. With key on and car not running I get 4.6V across the posts of the coil. Didn't think to take reading from the tower of coil but will next chance I get. What is happening? Something with the coil? Something with distributor?
Any help greatly appreciated!

Still have the ballast resistor? That may be the culprit

I had the same problem,
It happened to be the voltage regulator which was the original to the car, new one on and all is good again.

Ballast resistor with car off is .7ohm. Rated at .8

Check for a pinched wire.Been there done that.Rocky

rig up a jumper wire and jump the ballast. see if it will start and stay running for 5 minutes or so. you won't have it running long enough to hurt anything but it will eliminate the ballast as being the issue.

First thing I'd suggest is have a helper ready then when it does die IMMEDIATELY pull the coil wire (dist end) & hold it 1/4 from the intake metal surface (ground) & have him crank it (with the ign key) & see if you have sparks. Holler back when you can

Resistors will sometimes go open with the heat of current flowing through them. As previously mentioned, when it dies, jumper it. If it starts and continues to run, you've found the problem. Report back

Typically if its a ballast it starts on the key and as soon as you let off to just run it dies.In 50 years Ive never seen on run then die a minute or so later with the ballast.It eitehr runs when you crank and dies as soon as its let off or wont run at all.Notice i said typically.With replacing gaskets etc Id say pinched wire.Rocky

with all the above. my suggestion was just a place to start

I've traced wiring prior to posting this thread. No visible issues.

I have new regulator I'm going to install this weekend and try it. If it still dies I will jump the ballast. If it still dies... well.... I will bang my head against something.

Regulator wont kill it unless the battery is junk and has no charge.You can drive quite a ways without charging.First get a spark tester they are cheap.Then when it dies see if you have spark.If its still points check the condensor.Why do people think that if it dosent charge the ignition will die.It wont till the battery gets real low.
Rocky

I would suggest my coil wire 1/4" from ground test & if it sparks then I would pull the idle mixture screws and shoot a 3 second blast of starting fluid or brake kleen into each port (need a can with the thin red straw to get it up in there) then replace the idle mix screws. Count the # of turns in to lightly seated before pulling them to easily return them to their original position(s). Actually the first thing I'd do before anything is richen those screws a turn & see if it will idle/not die. if it does die, pull the yellow wire off of the starter relay to disable the starter & have a helper hold the key to "start" & you under the hood (quickly while things are still hot) & seperate the dist pickup zigzag pull apart connector and drag the male tip of the body half (your eliminating the dist "pickup" function) across the intake metal surface & see if the coil wire (dist end) held 1/4" from a ground makes sparks. holler back/more later. EDIT E10 ethanol is famous for the exact symptom you are describing. I'd forgotton about that cux even tho Nebraska is the countries' #2 corn producer, we have always had the choice between it & regular gas since the early eighties tho they are pushing it hard in advetizing nowadays something about 3 chemicals that reg gas produces that ethanol does not (I'm trying to remember the names) & they get absorbed into your bloodstream, dont know if that is valid or not but I do know ethanol wreaks havoc on fuel systems & is infamous for making idling engines die

did you try RR's suggestion? costs nothing to try...

How long must it be shutdown before start is successful?

Anything special on ignition system,,like an MSD or some such? Failing module getting too hot.

Perhaps coil or ballast is getting too hot for a reason and shuts down until cools. A bad coil could do this.

Are you running an electric fuel pump?

Stopped up fuel filter.

Wiring connector from ignition switch to dash harness. Wiggle this connector about when car fails to start. A bad pin or too loose female ignition switch side of one of the 6 wires or is it 5 could be at fault.

Same issue at bulkhead. Jumper wire from battery to positive post of coil is best test for either of these conditions.

Point distributor??? Check condenser and wiring to points from coil.

One would think it is related to the work you recently performed. Did you do anything else that you have not mentioned.

Again would be interesting to note how long car must sit before a start is successful.

I agree with Rocky: doesn't sound like the resistor, and certainly not the charging system. Are you running points or electronic?

My time is limited in working on it now because I'm in the process of moving. It's always set over night. Now it won't start but tries to when i let off the key. I'm running MP electronic conversion with chrome box and MSD blaster2 coil.

I disagree. I had a ballast resistor go on my '71 Hemi Charger back in the early 80's. I was driving down the road & all of a sudden it just shuts off. I coast to the shoulder & put it in park & it restarts, & I drive another mile, then it dies again. Repeated several times until I get to my buddy's house. There it sat for 2 weeks. We replaced the coil, dist. cap & pickup, & the Chrysler electronic ignition box 2x. Checked for spark, fuel, etc. All seemed in order. I finally decided to drive it home 20 miles away & made it, but the problem persisted sporadically for the next few days. THEN, one evening with it getting a little dark out, I had the hood up with the engine running & I was looking under the hood when the ballast resistor arced & I saw it. I re-started it & then wiggled one of the resistor wires & it arced & immediately died. I had an old used one in my tool box & installed it, the problem was eliminated.

SO, that being said, if you have another ballast resistor, just change it out & see if that fixes it. Easy, cheap, & quick.

Was the loose connection on an end where it could be soldered or on the resistor coil itself & not fixable?

Sunroof if I read it right you had a bad wire connetion not a bad ballast.As said typically when a ballast 99.99% of the time the car will start then die when key is let off.I did have a ballast go once that would not even start.It was one I never had in 50 years.Its always possible that a ballast can crack but have enough contact to run then quit but thats not typical.Rocky