Dual msd set up?

[mexracer10]

I am about to wire up my 7s truck and i want to put in the dual msd boxes and 2 coils and have them set up on a switch coil 1 and coil2 box1 and box 2. Now my question is how do i wire the tach? Do i need a spliter and if so where do i get one? I know that i need a coil selector switch, does that have one output to the tach??any info will be appreciated.

[Race8100]

We wired the same setup on our 8100 truck. MSD provides a wire output that goes to the tach. it's pretty straightforward. Since you'll be using a selector switch to determine which box you're using, the tach will get it's signal from that. Just jump the tach wires from the MSD box into the tach wire, and you'll be all set.

[Brutpwr]

MSD sells a tach splitter for the tach output when used on dual MSD-coil set ups. It's basically just some diodes so you could duplicate its function fairly easily if you don't want to pay MSD's price!

Jason :)

[mexracer10]

yea i paid like 3 dollers for the diods at an electic supply store and all that i orders is the automatic coil selector thing, and wallla i have an msd back up all ready to go.

[Brutpwr]

We have the MSD coil selector but have been told it does not work well so we did not use it. We have to manually move the coil wire over. Let us know if it works out for you guys and is reliable.

Jason :)