i see a lot of cars with the msd boxes in them and everyone says they work great. i understand that you have to wire it in to the distributor and the module is bypassed. besides the coil rotor and cap, is there anything else it uses or doesn't use, i.e the pickup coil,etc? thanks for any info

I saw you posted this at C4VR...
I haven't dealt with an MSD box in a hunnert years...I don't remember what all they entail anymore, but I'm pretty sure you'll need to use the original pole piece(pick-up coil), and prolly an MSD specific coil....
Hopefully someone that actually has one will chip in with some info.

I have an MSD 6A in my '69 but since I don't have HEI I really can't answer your question on wiring.  The only thing I noticed after installing and opening the spark plug gap to .040" is slightly easier starting...if there's any better power or performance otherwise I really can't feel it.  Maybe it can be measured on a scope or computer but not by the seat of the pants dyno.  

Dwain(longhorn294) had an MSD6 box on his car before...don't know if he still do or not, but he did have the destuctions, and wiring info. I made copies of it all once, but it got fried when the 'puter I had at the time took a doo-doo. I MAY have saved it on a disc somewhere. I'll look this eve, if no-one else can help.

I never had any luck with C.D. systems, and when they go out on ya  just call the "roll back" to come and get ya cause you ain't gona fix it on the  road unless you are carring a spare, another thing CD boxes don't  like is heat, might want to consider mounting the box inside the corkpit, also you may also pick a buzz in the audio sys., other than that alot of people like em.

well today i finally got the answer. never thought of it until today, i called the msd tech line. the tech told me that it also does not use the pickup coil. as joel pointed out, i had a problem with my 90. figured it was the pickup coil (replaced module first)and being it was twenty years old i ordered a rebuilt one. installed it and car ran great for about 10 minutes and quit again.

i have a msd 6al box and was considering whether or not to install it but no one could give me the answer about pickup coil. got a replacement for the replacement and installed it tonite and car runs perfect. ran it for about half hour, shut it off. restarted after a bit let it run and then took it for a ride and still is running great.

thanks for all the imput.

So, you think it "fixed" now? Sure hope so. It's getting to where you just can't really trust anything you buy anymore...especially electronic stuff.

got to think positive on this. it just got to me after going thru the pain of replacing the distributor to get a defective one. understand that's the chance with a rebuilt one but new ones cost a lot more. keeping my fingers crossed.

ME fingers and tootsies are crossed, also! Ya never know....it's weird how one will work fine, and the next one won't make it out of the driveway. They just don't make 'em like they used to...

Sorry to be a Johnny come lately on this topic. Dave, If you decide to install the MSD, spin by my house. They are simple to install. It does bypass the module and it basically manipulates the power from your existing coil. You can use your current HEI coil, but if it's aged, I'd suggest getting a new one.