Tach Under Hood Wiring

I just purchased a reproduction tach for my 1967 barracuda survivor (no tach origionally). Does any one have a pic or description of the coil wire, color routing etc. I want to make it look as though it was born that way.

I don't have a pic handy but I can tell you that it is a grey wire poked unceremoniously through by itself and runs from the back of the tach to the coil. Next time I'm out there I'll snap a pic of it. I'll also try to scan my wiring diagram and include it too. Geof