Tach setup question

[thachevythang]

I found a gauge overlay for my 85 silverado. It comes with different speedo & tach, fuel, temp, etc. gauges to customize to your liking. My question is, how can I switch the fuel to the clock postition (do not have a clock on the cluster) and how can I make the original fuel area the RPM? What do i need to do to make the speedo read the new 100mph correctly?
This way is alot cheaper than autometers, about 100 bucks with new gauge led, gauge overlays, heater a/c overlay, install kit, needle paint, and polish!!! as always help is appreciated

[Captkaos]

Sounds like you got 73-80 overlays.  You need a the specific printed circuit to move the gauges around along with generally the correct cluster to move them around, in addition to the gauges.

It may be cheaper that autometers now until you start looking for that tach, most aftermarket replacement factory tachs are around $400.  You can retro fit a Camaro tach from an 80's model but you need the wiring also.

Basically in the end you would be better off finding a 78-up cluster (that will fit your truck) or getting the autometers as they will be more accurate.