Are you saying the GMC pos. ground would fail with a neg. ground system? Would I swap + - posts on the gauge? Don't know, just posing the question. I looked through both the 39 to 50 something GMC Master Parts Books that I have. The electric temp gauge is listed as a bunch of different part numbers over that range of years, but there are NO listings for electric temperature gauge sending units. Like Dan says, finding the right one is going to be tough.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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