- Joined
- Oct 30, 2019
- Posts
- 3,155
- Reaction score
- 7,324
- Location
- Downingtown, PA
- First Name
- Wayne
- Truck Year
- 1974
- Truck Model
- Jimmy
- Engine Size
- 350
The tach with the fuel gauge is from the square body medium duty trucks. The 4000 RPM is a diesel engine. The V8 gas engines have a 5000 RPM combo gauge. It is not very hard at all to replace your large fuel gauge with the combo gauge.The tach with inset fuel gauge is probably from a heavy duty GM truck (don’t recall the exact model), since it only goes to 4K rpm. The HD truck cluster is the same physical size, and apparently can be adapted to a squarebody.
You can use your old cluster. Need to cut a hole in the back for the combo gauge to fit. Need to remove the fuel sender wire from the the large gang plug. From there you just need wire and connectors.
Both new gauges need ign pos. and ground wired to them. They each need their 3rd wire. Sender wire to th fuel gauge and a new wire run to the dizzy for the tach.
Tape the unused contacts on the print and put it back in place for the dash and turn lights.