Assuming a negative ground system, the rule of thumb is that the battery + connects to the starter and then to the ammeter +. All other loads and the charging system connect to the ammeter -. Once connected, turn on the headlights. The ammeter should show a discharge. If it shows a charge, swap all wires + to - on the ammeter.
'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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