1958 Chevy Apache Classic Instruments Gauge Cluster Install - Tach-Force

We determined the best course to route the pulse generator's wiring harness was directly in place of the original speedometer cable.

Notice how we routed the pulse generator harness straight up the back of the shifter and directly up to the cab floor then attached it to a factory clip intended for the stock speedometer cable. The idea was to ensure the pulse generator harness would run as far as possible away from the truck's exhaust system.

With the pulse generator harness routed along the frame, we continued it up the firewall alongside the main wiring-harness and poked it through where the main wiring harness enters the cab. Tie-wraps were used to attach it to the main wiring harness.

Next in line was to run the wiring (one wire) for the coolant temperature-sending unit.

The Allen-headed pipe plug was removed, and the threads were chased with a tap to ensure the sending unit would thread properly.

We used Teflon tape on the brass sending unit to prevent leakage.

Using a crescent wrench adjusted to fit snugly over the flats we tightened the sending unit down. A continuity light was used afterwards to test the brass sending unit for a good ground.

Teflon tape was applied to the oil-pressure sending unit to ensure that it didn't block the unit's orifice, which would cause it to give a low (or zero) reading.

It was necessary to thread this 1/4-inch brass gooseneck (included) into the oil galley next to the distributor first to raise the oil-pressure sending unit high enough to clear.

With the gooseneck installed, we were then able to screw the oil-pressure sending unit in and then check it with a continuity light for a proper ground. Classic Instruments advises against using Teflon tape because it might interrupt a proper ground.

Because the Tach-Force comes standard with LED lighting, these stock instrument light sockets will not be necessary.

These three wires (red, black, white) originate from the pulse signal generator, and were connected to the speedo/tach harness as explained in the installation manual.