The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - MSD-6AL with HEI ?

**MikeB** · 12-23-2023, 07:05 PM

Yes, you can add it to an HEI. Hard to say if it's worth it. Depends on what you're looking for. Its advantages are better spark at higher RPMs, and multiple sparks up to 3000 RPM for more complete combustion.

It does mean another point of potential failure, but I've seen them last for a decade or more. Good grounds and spiral wound plug wires are pretty much required.

From 6a and 6AL instructions:

MULTIPLE SPARKS
The MSD produces full power multiple sparks for each firing of a plug. The number of multiple sparks
that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft
rotation. Above 3,000 rpm there is simply not enough “time” to fire the spark plug more than once,
so there is only one powerful spark

12-23-2023, 07:05 PM	#4
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,666	Re: MSD-6AL with HEI ? Yes, you can add it to an HEI. Hard to say if it's worth it. Depends on what you're looking for. Its advantages are better spark at higher RPMs, and multiple sparks up to 3000 RPM for more complete combustion. It does mean another point of potential failure, but I've seen them last for a decade or more. Good grounds and spiral wound plug wires are pretty much required. From 6a and 6AL instructions: MULTIPLE SPARKS The MSD produces full power multiple sparks for each firing of a plug. The number of multiple sparks that occur decreases as rpm increases, however the spark series always lasts for 20° of crankshaft rotation. Above 3,000 rpm there is simply not enough “time” to fire the spark plug more than once, so there is only one powerful spark __________________ Mike 1969 C10 LWB -- owned for 36 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- converted from 250-six to roller cam 350, Vortec heads -- sold 1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!