You might try Kramer Parts. I bought a sending unit from them about 5 years ago and still reads accurate. He calibrates them before shipping it out.
http://www.kramerauto.com


[img]http://www.imgur.com/hxlGUJt.gif[/img]
4-speed
3:54 Dana
13.01 @107.93 with street tires (not hooking up)