Well, the sending unit in the tank was new when I did the restoration. I see J.C. lists the same sending unit (30 ohm) regardless if it's 6 or 12 volts. I guess I'll just hook up the gauge and see what happens. If it kills the gauge I'm not out anything, but with 2 people saying it will work, I'm feeling pretty good. I'm trying to remember back to when I put everything together and I think I tried using a resistor without any luck. Fingers crossed. Thanks for the replies.