Looking for thoughts and experience on the MSD ready to run units as opposed to the external ignition module style. It will be going into a '79 302 we're building, cammed, ported gt-40 heads, vlalve springs, machining etc... Be 9.8 compression all said and done.

 

On a 79 vehicle ? These came with Duraspark, changing to an MSD will only lighten your wallet with no other change to the ignition performance. Going to the larger post type cap and rotor will help as will a hotter coil.

 

Really? So what is all the hype and hoopla about "upgrading" to an MSD system? Marketing?

Thanks for keeping my wallet heavy, I was under the impression that a complete ignition system upgrade would be light years ahead of the Ford system under higher compression I'll have on this new engine. At the end of the day, a better coil and plug wires will do the trick?

 

Yep marketing hype. It is better than a points setup. But not better than the factory Duraspark setup. I'm running the stock Duraspark on my 331 in my 77 Comet, with a Flamethrower coil, large post type cap, Ford Racing 9mm wires, std. Motorcraft plugs. It's good to 7 grand. Comp ratio is 10.4 to 1.

 

The idea with most aftermarket ignition systems is that they work a little differently than most stock systems. In most stock ignitions, the coil is an energy storage device which is charged by current flowing through the primary coil and generating a constant magnetic field. A trigger from either the points or some computer controlled module breaks the circuit, and the abrupt stop of current flow causes the magnetic field to collapse, which induces the high voltage in the secondary. Since the coil only charges when it's not firing, if you have a high-revving engine, the amount of time available for charging is diminished at high rpms.

Most aftermarket ignition amplifiers, like MSD, use a capacitor that is constantly being charged, and the firing sends an energy pulse from the capacitor (capacitive discharge) through the primary of the coil, using it as a step-up transformer, to generate the high voltage. The idea is the capacitor being constantly charge will always have more than enough energy to light a spark, even at high rpms. The MSD units also send out multiple sparks per firing event to help light up mixtures under difficult conditions, such as high pressure forced induction.

The Ford Duraspark systems use the coil as storage device, but they are very high voltage ignitions, and much improved over old style points ignitions. Plus they have a feature that retards the timing while the engine is being cranked to let it start easier.

I'm in the process of converting the points ignition system on my 69 Mustang to DS2. Initial tests indicate that the engine starts easier than before, and it kept the function of the stock tachometer, which most aftermarket CD systems will not.

 

I am a huge Duraspark fan. But add a MSD 6AL box and coil to the Duraspark system and it will outperform the stock Duraspark set up. I've ran this set up on quite a few vehicles/engines. The MSD box always performs better and also increases fuel mileage. There is no contest.

But there is no need to change to the MSD distributor. Stick with the Duraspark distributor. Rebuild it if it needs it. That way if you ever have an issue with it, finding replacement parts will be much easier.

You can use the stock DSII ignition module to trigger the MSD box. And doing this also gives you the benefits of both systems. And also the option, if the MSD ever fails, just unhook the MSD box and run it on the DS II module. It's basically like carrying a spare ignition module with you.

 

Cool beans, thanks everyone. I had myself convinced that an aftermarket ignition system was the way to go! I'm going to stick with my Ford ignition after these insights

 

I put an MSD ready to run in my 79 Bronco. Its been in there for over 5 years and many 4x4 trips. They biggest advantage for me was the ability to easily set my timing curve with the springs provided. Many stock Duraspark setup have a very gentle curve for 70's emissions. The MSD was night and day for me. My Duraspark was also 35 years old at the time so that also plays as a factor..

 

MSD isn't what it used to be. I have seen many complaints about their stuff not lasting like it used to in the Mustang Forums. If you are looking to clean up the engine bay, I can highly recommend the DUI HEI type distributor from Performance Distributors. It's a simple 1 wire hookup. I have one in the 351W in my 63 F100 and it works great.. The old Duraspark ignition that came in your truck it also tried and true.

 

Only drawback to the HEI is they're huge and fuggly. on a 302.

 

It's like a model with a wart on her nose. Hey look at me, I like to run chevy parts on my Ford!

All joking aside. The Duraspark distributor with a MSD box is hard to beat. And it's not like you need to be a NASA engineer to wire one.