msd 8910 tach adaptor with mp dist

The signal out of the tach port on the MSD has a wave form that many tachs do not work or work correctly with, that is the reason for the tach adapter. The number of wires on the tach has nothing to do with it. The MSD instructions has info on which brand tachs typically work without the adapter and which ones require it.

Doesn't make any difference what you are using for a distributor either. If your MSD ignition is connected correctly and the engine runs the adapter does not interfere/modify that wiring.

I don't remember the wire colors for the tach adapter (if you don't have the instructions you can down load them from the MSD site).

Basically the tach output on the MSD ignition box connects to the input on the adapter and the tach will connect to the output of the adapter. The adapter also needs switched 12 volts and ground. With an MSD ignition the tach will never connect to the coil or distributor.

But before buying the adapter I would try your tach connected directly to the tach output on the MSD box and see if it works without it.