- Do you have a mechanical oil-pressure sender (metal line/tube) or an electrical sender (wire lead)?
- 12v wire lead used on 1955-2nd (I think) through 1963 235/261 truck engines.
- You should consider using a Runtz-style voltage reducer if you want to use an original 6v fuel gauge/sender. Also, the sender must match the resistance needed for the gauge (the sender/gauge resistance changed sometime in the late 50s).
- The earlier oil pressure gauges displayed up to 30 psi (I think) and the higher-pressure gauges displayed up to 60 psi (I think).
To get away from after-market gauges,
- go back to 6v gauges,
- use a Runtz-style resistor with the fuel gauge (or, change back to a 6v electrical sytem),
- use a mechanical sender with the original oil gauge (but, the reading will be at the high-point of range, if your oil pressure is good).
