The best voltage reducer ever made is the Vol-Ta-Drop, but the company went out of business years ago. If there was more demand, I'd make those today and sell them. It used a simple coil of resistance wire to drop the voltage. Accurate and fail-proof. If you ever see a working one on eBay or elsewhere, it wouldn't be a bad idea to buy it. I have one I got nearly 50 years ago when they sold for $7. It will still be working when dinosaurs return to the earth as long as nobody monkeys with it. I imagine somebody is going to show up and suggest you use the Runtz gizmo. I'm not a fan of that one at all. Converting the gauge itself won't be nearly as easy as you might hope it would be. If this is your hope, you'd be better off making a fuel gauge out of an early 70s pickup fit the AD cluster and swap your 0-30 ohm sender for a 0-90 ohm sender. I may actually have one of those fuel gauges at home. Will look to see if you want when I return. Just send a PM if interested.
