At low RPM the MSD produces a series of sparks during each firing instead of one like a conventional ignition. At low engine speeds when the air/fuel molecules are not finely atomized, the multiple spark feature still ignites the mixture. But this isn't the only feature. The number of sparks produced by the MSD Is reduced as engine rpm increases simply because "time" becomes too short to repeat a spark. However, the spark series always lasts for 20 degrees of crankshaft rotation no matter what the rpm and no matter whether it is a single spark or a series of four or five spark. This 20 degree duration spark sequence insures that the air/fuel mixture is ignited and completely burned. Also each spark the MSD produces is an extremely high current spark. Current is like the heat of the flamethrower. Current is what actually does the work or in this case ignites the fuel mixture. Together, the multiple sparks, the high current and the 20 degree duration, produce an ignition that is superior to any other ignition. More importantly though, the MSD Ignition ignites the fuel mixture in the cylinder instantly and insure complete combustion, no matter what the molecular composition is. The result is reduced variations in burn times and therefore more engine power, better throttle response, easier starting and better fuel economy.

I have a stock 77 HEI with 8mm magcore wires and never get any hint of misfire. I think the stock HEI in good nick is more than adequate even during worst case cylinder pressure/ mixture scenarios. And I don't have EFI. Less add ons is less to fail at a bad time. The only good time for a failure is in your climate controled garage with all your tools right there and no trip planned.

But, I found an old friend on E-bay. the same antique CDI that I had 70k+mi and 5 years experience with way back when. That was what it needed. But it was a ~40yo box and some time later C1 (1.5@600) died. (That is just for the E-types reading.)

Hey Matt:

Quote:

But, I found an old friend on E-bay. the same antique CDI that I had 70k+mi and 5 years experience with way back when. That was what it needed. But it was a ~40yo box and some time later C1 (1.5@600) died. (That is just for the E-types reading.)

My guess would be a "Delta mark 10 CDI)

I had one on my 63 Pontiac Parisienne. It had a 327 4 barrel and I usually had my foot in it (I was a lot younger then) seldom fouled a plug after I installed the Mark 10 loved it. (I built it from a kit!!)

Best Regards

Ah-- the narrow track Canadian Pontiacs

The newer one is a Mark 10B.

I still have two of those NOS in my garage. I also think I also have used one around somewhere. I used to sell those in the early 70's.

Well, my toad got harder to start till it won't start. It's fitted with a Summit hi energy system, which is an HEI just like my coach excepting the cap is blue instead of gray. Anyway, I had the Advance place test the module, works fine. Took the cap ass'y and stuffed it in the coach, fires right up. So, I just picked up eight new sparking plugs to replace the crudded up ones in the toad. Hopefully it will run now. Toad PO had put a set of very cold dragstrip Densos in it, you can't see the electrodes for the carbon. If this don't work, I guess a new pickup coil is in order although the one in it measures the same as the one in my coach, leading me to believe it is working.

--johnny