Summit states they have a MSD box that "piggybacks" the existing factory ignition system. No cutting wires. Any idea how that would hook-up? Is it a deal for $240?

 

In my opinion, those are nice to have for competition use, or with older ignitions.
But honestly, does you ignition do what you want now? To me, $240 down the drain. Cause after its installed, and you start the truck and drive, you'll no doubt say "So?". Now you have multiple spark, and more power. But do you feel it?
If you have an older truck, it might help, but don't let the hype get you. My $.02

 

yeah i think you'll be set if you just change your packs if they are old...

 

I have the Jacobs ignition and I will agree with Linetest and ROUSHFAN-1. It has probably caused more trouble then fixed. The plug wires that come with it are the worse and there are sparkplug issues that require changing at least yearly.
I did get a small milage gain especially under load when I tow.
If you are concerned then get a set of Accell coil packs.

Just to add, I have not removed the Jacobs because I plan to Supercharge in the future. At that time, the Jacobs will no doubt become much more valuable as a performance product.

 

Thanks. That helped make up my mind. I'll just leave wellenough alone. I would consider getting the MSD coil packs, though.

Right now I've got beef with MSD because the 5 series box they said checked out doesn't work in my brother's 89 F-150. I've had it since April of 2001, and have used it for maybe 7 months. When it worked, my gas mileage went up from 17 to 19 in my t-bird and 15 to 17 in his F-150. Great when it works, sucks when it doesn't.