Anyone out there running 2 MSD boxes (leading and trailing?). I have a couple of questions I couldn't find answers for through a search. I have one box on the leading with 2 coils running direct fire - I want to add another box for the trailing using one coil through the dizzy without the ignitor. Would direct fire (2 coils) for the trailing be of any benifit or worth the extra $'s for another coil? Can I run two 6A's? Anything out of the ordinary that i should know about wiring in the second box (different from the procedure for wiring the leading box)

Anyone with this set up? Any recommendations? Apprec. any help / advice

Note: this is for a 12A application (1983)

 

You can not run your trailing direct fire like the leading. If you did you would be firing into the next compression stroke. You can how ever wire the MSD box just like you did to the front and route the spark through the dizzy. Use the leading plug holes on the dizzy for the trailing since there is only one air gap to jump across.

 

alot of money for very little to no gain.

 

I have an extra box so it's no investment.

So, I can run the second through the dizzy with one coil - correct? Any timing adjustment required and is stock timing OK? Where are you guys running the power thin red wire - does it matter as long as its a power supply "ignition on" only? I can lose the trailing ignitor also? thanks guys

 

Damn.... i wish i had a box..

 

sell it and invest in something that will actually boost performance. your not going to gain anything but clutter in the bay. if your gungho about it you can use one coil and the dizzy but not sure on the igniter.

 

You don't need the ignitor. Take the signal for the MSD from the pickup just as you would have for the leading ignition.

 

Thanks guys

Jeremy - I'm fouling my trailing plugs and I hope the MSD will help with that problem - I'm using 2nd gen platinum plugs which are $20 a pop here in Canada (3 sets of plugs = the price of a 6A)- in the long run I think the MSD will save me money. It certainly did a good job on the leading when I first installed the direct fire set up a few yrs ago. If it doesn't help, I'll sell it.

 

just change the heat range on the plug or use 1st gen plugs on the trailing. that would be a far simpler change. it seems you're pulling the engine to change the oil so to speak.

 

dont 2nd and third gens have direct fire waste spark on the leading and trailing. whycant you do it on a 12a.

 

no

 

have you even tried a simple blaster 2 coil on the trailing?

i would try that and some ngk 1st gen plugs first

 

I'm using a performance Accel coil on the trailing now. I've also used 1st gen trailing plugs and fouled those as well. I'm going to hook up the MSD this weekend (only takes a few minutes) and try it. I've heard from others that 2 MSD boxes is a worth while upgrade and may solve my problem - I'll post the results over the weekend. I could be wasting my time but now I'm curious - since I have 2 boxes, what better time to do some experimenting?? Thanks all!!

 

its all you man. try and get some performance gains recorded by something other then the butt dyno.

 

Let me know how it works out 'cause I have 2 MSD 6A boxes lying around I want to use.

Mike

 

What about putting both boxes on the leading? One box per coil? Any gains there? Especially over 8000rpm?

 

I Had to mail one box away for repair so I'll be awhile before I post any results.

I've heard of 2 boxes on leading but that's not what I'm going after. I want a smother all round ignition (leading /trailing), not necessarily big performance - I'm very rarely up around 8K RPM

 

is this okay to do? how do i do it? or should i run an msd to leading and trailing. direct fire only on the leading.

 

ya from what i hear msd doesnt really add much at all... but since you have the stuff already you might as well

 

I am almost there and I am stuck. I cant figure out how to wire up my two msd boxes in my car. Is there anyone down here in san diego that can help me out? I will gladly pay you. Or can you recommend a good shop?