Understandable. We dont have time to be experts on everything or even know what to ask at our first time around, yes I will gladly entertain your questions. smile For starters, I was worried about blowing up the gauges somehow by using 12v bulbs without a reducer. I now know the gauges can be separate from the bulb current.

More, I have ripped out any and all wiring from this 83 yr old truck. Converting to twelve volt with totally new harness/alternator etc..and would like to use original gauges for originality. Learning as I go.

1. Do you have a 6V or 12V battery? yes 12v, I have to do that to use 12v bulbs I believe
2. Are you in the process of converting to 12V? yes
3. What are you doing? See 1 and 2 (I think)
4. What motor do you have? What year motor. In original post 292ci, '84 but converting to one wire system (just learned what that was)
5. Foot start? No, I am going key start.

I think you need to wait and be careful until you explain what is going on. All we know is you are asking about bulbs. Senders are not voltage dependent.
You say: I *thought* 12v bulbs work with 12v system.. or am I missing something in regards to the gauge housing?

You also ask if you should use 6V or 12V bulbs. If you are indeed converting to 12V, there are a whole lot of things to know. If you use gauges, electric motors, bulbs, coil..... that are from a 6V system, in a 12V conversion, you will burn them out!!!!!!!!!!!!
I agree totally. I was worried about blowing up the gauges somehow by using 12v bulbs without a reducer.

More learning:
The AMP gauge brings AMPS INTO your cabin, and I learned some folks tie it into ignition. I have also heard this blowing out everything on a bad day and truck not starting.. I dont think I like that..
The oil gauge is mechanical and literally directly connected to the oil.. as an oil filled line. I dont think I like that.
The water temp gauge is mechanical, it is also similar to the others. I can see my self keeping the gauges, maybe using the water temp and oil pressure.. but getting a separate Volt gauge.

After learning all of this, I am also looking into modern gauges that fit right into the original dash holes for the '38...


'38 1.5ton; "The stuff is as tough as woodpecker lips"