MSD Tach Output Question?

Normally there is no return noise coming from the tachs and I would have a hard time believing there would be any from your gauge. Those two alone should work just fine. The fuel controller may turn out to be a loose cannon though. I would recommend temporarily connecting those three items one at a time in order to ensure no hiccups along the way.

What sort of trigger do you have? If you've got an optical dizzy I would recommend hooking your fuel controller to the dizzy rather than the MSD tach output since it will be a cleaner signal.

Sorry, there are basically four ways to get your trigger signal which tells the MSD box when to fire the coil.

1) Hall sensor - The most common type and the oldest as well. Basically an electronic break in the internal workings of the distributor.
2) Optical sensor - A small photoelectric mechanism inside the distributor sends the signal as the rotor turns causing small slits to activate the sensor.
3) Points wheel - Usually a magnetic wheel attached to the front of the crankshaft. The most accurate of all the types but the most expensive as well.
4) Variable Reluctor - Similar to the points wheel but the magnets are inside the distributor.

The MSD Pro-Billet basically uses a VR trigger. In this case you'll need to hook the dizzy to the ignition box and hope that all three of your items will work together nicely.

If for some reason they don't seem to work well together, you may want to try installing a low-amperage stereo filter on the fuel controller line to take care of any noise that may be trickling back.

I honestly don't foresee any problems with your setup though.

Well no. In most cases (including yours) the tach output provided by the MSD box is perfectly capable of providing RPM information for whatever item you need. Have you tried hooking these things up in parallel yet?

Not really the same as what you are doing, but I hooked my Digital 6 tach output to the stock 82 tach wire and one of those Proform shift lites, and it seems to work both just fine.

I unhooked all of the Duraspark box plugs, and am triggering with the stock distributor pickup. (Carbed 5.0 setup)