Aftermarket Ignition

[Mrturner1]

I've been looking over the Jegs catalog and thinkin about getting the whole ignition system upgraded to MSD. I know what the distributed does, but I was looking at my engine yesterday, and I don't see a coil (like the msd blaster for example). So is this an add on type thing or am I missing mine? And what's the benefit if it is just aftermarket? Also lookin at an MSD 6A box, if there's something better for a street/strip weekend ride let me know. And also what's the benefit of that as well?

I know more fuel/air/spark = more hp and tq, so do the 6A box, the coil, and the distributor all have a place in making more spark, or are they just sellin parts?

[davepl]

If you don't have a coil, odds are you have an HEI which is bigger but integrates it into the cap.

Unless you are having a problem you need to solve, don't change a thing.

Ignition is one of those things that works or doesn't, given a particular plug gap. A more powerful ignition allows you to run a longer gap increasing the odds that an air/fuel molecule combination will get hit.

Such things are only of concern, really, when you start talking about 12:1 compression or forced induction where there's so much air mass in the plug gap that it's hard for the spark to jump, so you need to upgrade it.

The days of everyone needing to bolt in an MSD 6, a big yellow coil, and all of that are long gone.

If you didn't already have an HEI (were still ruinning points) I'd suggest you install a Pertronix II module in place of the points just as a reliability feature.

Like I said, unless something is actually failing, investing in ignition beyond your needs yields zero power increase and is a poor place to invest for performance.

Save that money for head porting! Actually first spend it to get everything running perfect at it's current power level (few do this important step) and then look to cam and heads, that's where the power's at. And while you can't/shouldn't port your own heads yet you can likely do the remove and replace labor yourself, which is a big but doable project.

If you have a lot of traction, I think we talked about a converter in another thread. That's another place where you can invest fairly cheaply, get a nice performance bump off the line, but have to live with it the rest of the day - just like a big cam. Head porting adds power everywhere from about mid-lift up without messing up other RPM ranges.

[GASoline71]

You probably have an HEI which has the coil in the cap.

The 6A and 6AL boxes give more spark hits per degree of crank rotation. MSD actually stands for Multiple Spark Discharge. They also provide a hotter spark and won't drop voltage at higher RPM.

The only difference between the 6A and the 6AlL, is the 6AL has a rev limiter.

I have an MSD Pro-billet HEI and a Digital 6AL in my rig and love it.

Gary.