Tom:
There is an MSD adaptor that is usually furnished with the tach, and you need it to do the install. It is a small unit that mounts under your dash. Your tach has three male spade connections, input, output and ground....the adaptor has four - input, output, ignition and ground The MSD module has a recessed spade connector on its side that runs a single wire to the adaptor.
Installation is very straightforward, and if you have purchased the Smiths MSD adaptor, the instructions that come with it are very clear.
Bud
