The Stovebolt Site Forums The Shop Area The Electrical Bay Using the original gauges

I have a 1938 Chevy 1/2 ton that has a 350ci and auto trans. My question is "Should I use the original gauges or go to new ones?"
The interior is totally gutted right now and the previous owner had hooked a cheap gauge package under the dash, which I took out. The old gauges look good but were not hooked up. What needs to be done, using the old gauges with a 12 volt system? Is there a way to tell if the gauges are working correctly?
I will be rewiring the entire truck and reinstalling the dash after that, any help would be appreciated.

Rich38Chevy,

Your new charging system will output much more current than the original ammeter was designed for. Under the worst case scenario, this could peg it for a second or so and might injure the movement...this is a guess.

The oil and temp gauges were originally made for values much less than your new SBC will develop. You might find these meters pegged too.

The mechanical temp gauge was probably mid-scale at 160&deg while your new engine is going to be at least 180&deg. This might push the limits of your gauge.

I have not done this conversion so this might be bad info! Lets see what other folks have to say.

Stuart

You might check the classifieds at Hemmings Motor News. There are several folks who advertise gauge restoration. They might be able to modify your originals to work with your new set up & keep the original look.

they have a thing that you hook inline on your guage to step it down to 6 volt so it wont damage it wish they would have had that years ago anyway there cheape then you can run with your stock guages cheaper then getting yours restored but mayby not better

the only gauge you need to deal with is the gas guage and chevy of the 40s has a reducer, the oil pressure, and temp are mechincal, and made sure you dont use a alternator that puts out more than 65 amps, so you can still use the amps guage

John is right, the fuel gauge is the only electric gauge in the truck. Get a step down voltage reducer and it will work just fine.
The oil gauges read to 30psi but will work with late model engines, mine has for 7 years. I know it has at least 40 to 50 psi oil pressure at road speeds, and it drops to 20 when hot at idle so I don't worry about what is truely has. As long as the needle moves, it good enough for me. GMC's used a 60psi oil gauge that will bolt right in your Chevy gauge but the decals for the faces are different colors. If you can find a restoration shop that makes there own decal faces, you could have one custom made. I have one of the gauges, but I'm to cheap have one made. One of these days I will figure out how to do it with a scanner and printer!
I had to have the water temp gauge rebuilt with a longer probe line to reach the front of the engine, but it works just like the old one.

Joe

Thaks for the great reply's. I'll look into getting the reducer then start with the fun of rewiring and putting the cab back together. Can't wait to get it back on the road.

Rich