I give it about a 0.01% probability of being the problem.

You are discounting a faulty coil wire as the source of the symptoms he is describing?

Absolutely!

One of the symptoms is backfiring, most common cause would be A/F mixture "ignition" while the intake valve is still open. Hard to have backfire if the HV never reaches the distributor.

Over the years I have all to often used to much force and separated the HV wire end connector. Pushed the wire back into distributor/coil tower, DRIVE until purchase new wire. If the wire center core is within <0.10" of the distributor/coil contact it will "jump" just fine.

Oh well, thanks for politely giving him a 0.01% chance.

If an engine backfires, stumbles etc. could it be a result of unburnt fuel from the previous revolution?

OK, the wire turned out to be a false fix. I got it in, it started up and ran a little rough, but I figured that was due to poor timing. I drove about 10 miles on back roads and it was OK.
After helping my son carry his new fridge up the stairs into his condo I decided to run to an auto parts store and pick up a timing light and dwell meter. Well a timing light is easier to find than a dwell meter.
Pulling into the third auto parts store the car started backfiring like crazy. After I came out I decided to try to get it home on back roads. This only made it about half a mile. I was backfiring so bad people were running for cover thinking it was a gang shoot out.
I got help pushing it into the lot of a 7-11 and popped the hood. I checked the connections again, but did not have any success. A friendly guy stopped to help and we checked for spark. We were getting no spark to the distributor. After figuring that the connections were all good we isolated the problem to the coil.
I called my wife and had her bring over the old Bosch coil that I had taken out with the MSD upgrade. I got the old one installed and it fired right up and ran like a champ all the way home. What I thought were misses before were likely shorts in the coil. I have read of guys getting bad coils before and I guess it was my turn.
The MSD was an 8222 High Vibration Blaster Coil. I just printed out the label for the RMA. I am hoping MSD will supply a replacement.

I have read that the old Bosch is not the way to go with the MSD ignition so I will be replacing it with a new MSD soon.

"Back"-firing into the EXHAUST?

Mixture ignites as the exhaust valve opens?

Possible.....

But I'm still not buying into the inability for the spark to jump that "broken" HV connection.

Ah, vindication....

The distributor cam, points, are designed such that the rotor "contact" will be positionally correct for firing the "selected" plug. So DWELL must be correctly set, 65-70%

I don't understand, completely, why anyone could design, or recommend (Wayne?) that a CDI system use an "I" core ignition coil. An "I" core coil is completely appropriate for a Kettering ignition system wherein the spark energy is stored within the coil's magnetic field PRIOR to plug firing, No high efficiency or QUICK energy "transformation" from the coil primary to secondary required.

Not so with CDI, the need to transfer spark energy from the primary winding to the secondary winding is co-incident with plug firing. That, in turn, results in the need for the coil to act as a transformer, QUICKLY accepting energy flow into the primary. The CDI's high voltage output, 300-500 volts, over comes primary winding inductance, while the E&I core laminations provide a highly efficient "closed" magnetic field, coupling the energy into the secondary more efficiently (~30%) than would a simple "I" coil open magnetic field "path".

Use one of these...

http://forums.pelicanparts.com/uploa...1397315605.jpg

Heads up!

Ford, for the past 2-3 years, have been replacing, under warranty, spark plugs, coils (COP), catalytic converters, even engines, as a result of plug gap no-fires. CAC condensate (water) ingestion results in compression pressures well above design specifications.

http://forums.pelicanparts.com/uploa...1397316058.jpg

Other than manufacturing defects the most likely cause for ignition coil failures is internal "flashovers", the insulative resistance for spark jumping from secondary to primary is lower than the design path, coil/distributor/rotor/HV wires/spark plug.

An out-of-position rotor due to improper dwell might well result in coil internal FLASHOVERS.

"...This was brought on by a no-start issue....."

Ignition points rubbing block worn down enough to increase the dwell to >90% and the 3 wire CDI system's input signal "anti-bounce" filter capacitor/network filled in the <10% "gap" = NO FIRE.

New MSD has less filtering so it "fires" but rotor mis-positioning (>90% dwell) results in enough plug no-fires that coil finally fails due to internal carbon path formed by multiple internal flashovers.

Pull the HV wire out of the MSD coil and watch the spark jump THROUGH the coil tower sidewall to the coil ground terminal as you crank the engine.

or these:

http://forums.pelicanparts.com/uploa...1397318024.jpg

http://forums.pelicanparts.com/uploa...1397318060.jpg

http://forums.pelicanparts.com/uploa...1397318120.jpg

http://forums.pelicanparts.com/uploa...1397318145.jpg

I tend to have preference for a HV connection DEEP inside the HV insulating tower.

OP:

Please check the point dwell and set it correctly, 65-70%, if needed, then check/set the timing by rotating the distributor.

And please post the results...SmileWavy

....says it ALL...!

http://www.msdignition.com/Products/Coils/Race/8222_-_High_Vibration_Blaster_Coil.aspx

100:1 turns ratio, maximum voltage, 45,000 volts.

MSD 6425, 530 volts output, 100:1 ratio 53,000 volts!

8222 MSD coil was designed, obviously, for use in a Kettering ignition system.

With a Kettering system the possibility for internal flashovers and the resulting carbon tracking is minimized via the condenser limiting the rise time of the ignition voltage. The spark plug wil often, or mostly, fire before the maximum voltage, in this case 45,000 volts, is reached.

With CDI the maximum spark voltage is reached virtually INSTANTLY in comparison. The second high voltage, in this case 53,000 volts, risetime is limited ONLY by the coil's inductance.

Another strong reason for NEVER using an ignition coil designed for a Kettering system with a CDI system.

I would have though the MSD engineers would know better.

The episode Friday night was due to me searching for a dwell meter.
It arrives tomorrow from Amazon so my son and I will work on the points gap, dwell and timing tomorrow night.
I did drive the car Saturday and had some misses at high RPMs at the end of an eight mile drive. Then on the way home I got my backfires again after a brief run on the freeway. I figured that I would just stop driving until the points and timing was done.
I thought about dropping in an electronic replacement for the points like the Pertonix Ignitor II, but I am tired of throwing parts at this problem.

set the dwell and points first. See if that makes it work.

Then think about the Pertronix. I have found it to be a great upgrade for a car with points.

or just trash can the MSD..........

Last night we made progress on the dwell and timing. The max we could get the dwell to was 29, the timing at idle is fine and we are 34 at 6000.

Setting the dwell is a pain and I will be looking up a Pertronix very soon.
In the trip to the gym and back it ran OK, but I didn't push it and on the way back at over 3200 RPMs I sensed it missing a little.

Could this be arcing in the old spark plug cables? so it that I need to replace the plugs and go to a wider gap? I was not having these issues before the new MSD and coil so I am trying to work my way through the system.

I am running the old coil since the MSD fried and I have not received the replacement yet.

Any thoughts?