Unless you are converting to a carb and regular electronic distributor staying with 6v is really taking on a can of worms because EVERYTHING that makes the 96 engine work is 12v negative ground. That said, of course your can use your factory gauges even with 12v. The only gauge that is electric on a 50 is the gas gauge which can be reduced by an electronic voltage reducer like a Runtz. The V8 will keep the oil pressure gauge pegged out but no harm done. Amps are amps 6 or 12. Dorman and Imperial have fittings the temp bulb will screw into and one of these can be installed in the rear water runner on the drivers side so the sender tube will reach it and save one from buying the high dollar longer tube one offered by Carter. Have picture if needed.

Evan