68 Impala Instrument Cluster Install

[Zach Carter]

So the cluster that I got had the pigtail for the dash harness still intalled in it. I matched all the wires to the dummy light harness and changed the coolent temp sensor, the oil guage is mechanical. Everything works. Except for the tach. Does anyone know how the tach gets it's signal? There are two wires left over from the guage harness. Solid black and black with a white stripe. I know I need to run a wire to the coil. Is one of these the wire I need to run?

Thanks