Hi, I've mostly just been a lurker here, but I've noticed this site seems to have the most knowledgeable members so I figure its a good bunch to ask.........I've been shopping for 1956 Dodge gauges for a custom panel I'm building for a project(49 Desoto club coupe). I'm finding 1950's Mopar fuel gauges seem to all list a different gauge for wagons...why? They look the same but have a different part number. My second question is about the gauge voltage....Did they use a 5 volt regulator like in the 60's? Between 55 and 56 were the switch over years from 6v to 12v the gauges look identical so is the 55 also 12v? If it were 6v then with the fact that it was designed for positive ground cause any problems? I also have a 57/58 Chrysler 300c 150mph speedometer with a very rough movement...Can I use parts from a standard 120mph speedometer? How were they calibrated?...through a different magnet?,....clock spring resistance?.....Gears within the mechanism? Any help will be greatly appreciated.