My buddy here at work is building a 52 Chev Pickup (S-10 chassis, bagged, LT-1, etc.) and would like to utilize the stock 6 volt gauges. What does he need to know? How about the stock fuel gauge and aftermarket fuel sending unit? Hopefully he'll register and pipe in on his own too! Not too shabby for his first build with only a couple months time and tight budget!
Aftermarket sending units usually have the wrong ohm rating to work with the stock gauge so he needs a correct 6 volt sending unit and a reducer BEFORE the gauge. The ammeter won't care if it's 6 or 12 volts and the rest is mechanical (oil pressure, temp).
check out those Chevy truck parts houses like Brothers, Jim Carter, The Car and Truck Shop. They sell new gas gauges for both 6 and 12 volt systems. The Ammeter doesn't matter because it's not measuring voltage. The rest is mechanical.
I've done may 6 to 12 swaps on old GM trucks.With stock gauges only the fuel gauge needs to be dealt with.A Runtz voltage reducer works best in my opinion.It goes on the wire feeding the gas gauge from the key switch,the stock fuel sender needs nothing to work properly.
Be careful with the stock ammeter! Even though it is a current device doesn't mean it can't be broken by charge rates of new alternators. Some are up to 140 amps, your gauge is probably around 30 amps max. You can solve this issue by shunting a resistor across the ammeter to pull excessive current around the ammeter. This is why new cars have voltmeters, not ammeters.
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