Just finished my 64 Savoy full rotisserie restoration. Now the car will not stay running. It will fire right up and run from between 10 to 20 minutes and then you can see the tach needle start to jump around a little then it goes straight down and the car dies but then you can hit the key and it will start right back up and do the whole thing over again. It has a brand new MSD pro billet distributor, MSD blaster coil and a MSD 6 A L digital box with rev control. The MSD box is mounted inside the car on the back side of the fire wall. I called MSD and they said it might be some interference so I installed a aluminum shield behind the box and still have same problem. I have tried a new MSD 6 A L box, A new coil, a new alt, a new voltage regulator, and nothing has worked. The battery is mounted in the truck and I have the ground going to the frame. I have another ground from the engine to the front frame. PLEASE any help would be great !! I have a killer new car and can't drive it. If you know anyone in the Indy area that works on Mopar electric problems please let me know that as well.
Thank you !!!

Where do you have the large wires for the box attached?They should go to the battery.Also make sure the dist hole in the block is clean and not full of paint.My 440 would not run till I cleaned the hole for a good ground.When it quits are you getting spark from the coil?Rocky

Might be the MSD dist. You said restoration so it's a SB I'm assuming. If a std electronic dist will trigger the MSD system & you have a SB electronic dist handy you could sub it in. When it dies is this at speed or at idle after 10-20 minutes of driving? & when you start it back up after it dies does it take another 10-20 minutes before it dies again EDIT on the chance that it is a partly plugged carb idle circuit you might afix one of those thin red straws to a can of starting fluid & shoot a 2 or 3 second blast into each idle mixture port. count the # of turns to lightly seated & you can easily/quickly return the screws to their previous exact position. As said I'd wanna check for spark when it acts up but it does immediately start back up which is confusing since it'd still be just as hot or almost as hot I would think but as you know electronics are strange. Holler how it goes. I ain't never owned an MSD product (yet) but the moniker the one guy (on here) put on it (Might Sputter & Die) always scared me a bit

If you think its msd problem, you can send the box to msd for testing.
I think you have a fuel problem.

Poster already said he has tried a 2nd MSD-Coil and distributor.. same problem.. Correct ?

Run the MSD power wire and trigger wire directly to the + battery post and see if the car stays running then report back

Also unplug the tach from the MSD - bad tach could short out the box

He tried a 2nd box (6al) but not the dist

Sounds like a fuel vent problem to me Does the engine just die or does it sputter like it's running out of fuel. The fact that it fires right back up rules out the distributor pick up.I have almost the same ignition except I have a Firecore distributor and my 6AL is mounted inside on the firewall too.I had mud dobbers put a mud plug in my fuel vent before and my car done almost the same thing.I changed the fuel pump before I figured it out
Gus

I had the same thing happen that Gus describes, only it was a prank where someone put a rag down the fuel filler & into the tank. Suction would get the rag over the sock filter and strangle the fuel flow. It would start back up because when it died, the suction went away. Drove me nuts until I pulled the sender and dropped the tank and looked inside.

UPDATE... I removed the MSD box from the back of the fire wall and just laid it in the floor on the passenger side and the car ran perfect. Even took it out and drove it for a hour and no problems. So there must be something where I had it mounted that the digital box don't like. Its crazy I have been jacking with this for two weeks. Now I will just relocate the box.. Thanks for the help !!

I'd say a loose connection as there is no magic. glad ya got it solved