Ignition system problem? Help!

At a loss trying to figure out this problem, had to step away from the car for a bit and now im back at it. Any ideas would be appreciated. Below is an explanation of the symptoms and things ive tried or replaced sorry for the long post.

After first getting the car in running and driving condition I could drive the car on 1-1.5 hour drives with no issues, only difference is I was running a borrowed carb which I gave back and swapped to another used one (at this time I have ruled out the carb on a different car) Tried to drive the car the 1 hour drive got almost home and it started acting like it didnt want to idle and from a stop would try to backfire if I didnt flutter the pedal, no biggie thought maybe carb was getting hot so I put a spacer and changed jets and idle jets in the carb. Went for a short drive and just driving down the highway the car began to backfire and sputter blew every vaccum cap off barely got her home. Tinkered with adjustments and no matter what I did it just got worse and worse till it just wouldnt crank at all. Next morning cranked right up and idled fine in the driveway for 15 mins. Tried new Ballast and new Ignition Module and at this point I can let the car idle in the driveway for 20-30 mins and runs fine just it just falls flat and dies. It will re-start but has no power if i rev it. Ive done this several times trying to pinpoint a problem...

Car doesnt get hot, it is getting fuel, runs and revs great till its run for approx 20-30 mins. If I can pinpoint the ignition system as a problem ive considered using a MSD box I have several I could slap on it.