[K10-Kansas]

I'm using an ACDelco Oil Pressure Sending Unit that I realized today doesn't list 78-79 c10 as a fit. It does list 1977 https://www.summitracing.com/parts/A...4/applications

I am using a gauge for 78-79 c10 https://www.lmctruck.com/1973-91-che...pressure-gauge

Is it reading high because I bought the wrong sending unit?

This one shows a 78-79 c10 as a fit https://www.summitracing.com/parts/s.../c10/year/1978

So maybe the make and model of the vehicle doesn't matter in relation to the engine dictating what sending unit to use but instead, the make and model of the vehicle dictating what sending unit to use per the gauge that was in that make and model?