My sending unit is bad on the fuel tank. Do you know if you have to drop the tank for access? I want to fix my old one if possible. I think it is stuck. Is it easy access? If not, I will order a replacement just in case it is too hard to do twice.
if the 66 is like the 65 you should be able to access it through the left wheel well behind the faux panel in the wheel well. Raf
$arge is correct, there is a panel just in front of the fuel tank...it makes up the back of the rear drivers side wheel well. Once you remove this panel, you should be able to reach up and remove the original sending unit. What has likely happend is that the float is filled with gas. Dearborn classics, and Macs sell full sending unit replacements as well as float kits. Brian