I am placing a order at Year 1 for wiring harnesses,and not sure which one to get for the tach.I have a 70 roadrunner,which had the rally gauges with no tach or clock,and i am adding a original Tic toc.There is 2 differant ones listed ,L38499 and TAC141.I talked to M&H and they were a little unsure and suggested HU6869.Has anyone done this Thanks