Does anybody know what the voltage output of the stock coil is ?, would replacing the stock coil with a high output performance coil do anything to help engine performance ?, if not would it at least provide more voltage to burn the fuel in the cylinders better to help lower emissions ?. im just looking for ideas to make my truck run better.

I dont know what the stock voltage is, but you can get an OEM "style" replacement with a hotter spark and gap your plugs a little wider... Help with emissions? Maybe.. Not as much as getting your junk tuned right!

I'm no engine expert, but my understanding is this:

A more powerful coil will allow you to produce a bigger/hotter spark, which will allow you to burn more fuel, making more power. You will also probably want thicker wires and to re-gap your plugs slightly larger. Its not necessarily worth it though unless you are putting more fuel into the cylinders, like from a weber carburetor, oversized valves, etc. Even then, its not gonna give you a huge amount of horsies..

-Scerb

I've been thinking about the MSD ignitions but not sure which one is a good replacement. Anyone have a suggestion?

I was recently troubleshooting an ignition problem and wound up buying a little tool for estimating spark voltage from Autozone. It's basically two pointed screws pointed at each other. You adjust one screw to change the gap and there are some markings on the body of the part to show what gap size corresponds to a particular kV value (so if you can get the spark to jump 0.25" then that is roughly some voltage value).

It cost about $5 and would give you a rough estimate of the voltage reaching your plugs.

If you have the equipment, I think you could pull the coil and send a low voltage, low frequency AC signal into the primary and then measure the resulting voltage on the secondary to determine the ratio. You're trying to get at least 20kV from 12V so the ratio is going to be big. You should note that if you change the ratio to get more voltage, you're going to get less current (you can't create more energy), which might be bad.

I have recently replaced my stock ignition with a Jacobs off-road ignition setup, as well as a weber 32/36 carb. My truck ran great prior to the swap with the exception of hard starting in the cold. I thought the ignition would help with the starting, but it ended up being carb. issues. Honestly I havn't noticed any real improvement with the new setup aside from the truck firing up on the first crank even in sub-freezing weather, but like I said, ran great before the swap. I'm slowly making my truck into a competent trail rig, so, I'm happy with the investment. <img src="/forums/images/graemlins/kewl.gif" alt="" />

I've run MSD units (6A/6AL) on carb'd setups and couldn't tell a difference. I can tell that an aftermarket coil produces a much better spark than the 20+ year old stocker.. Power wise, couldn't tell.