what year did GM switch to 12v? Recollections from my teen years are that Ford and GM switched in different years. In our trucks (with exceptions for some larger models) 1st series '55 were 6 volts while 2nd series 55 were 12 volts. An exception is 55 2nd series GMC with 248 engine and standard transmission was still 6 volt (and positive ground like the earlier GMC years back to at least 1939).
'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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