So, I figured after 54 years it would be best to replace the fuel tank and sending unit in my '66 Coronet wagon. I have had that new tank in and out of there 3 times now and finally today, shoved the 54 year old sending unit back in the new tank. When I try to measure the resistance of the two new senders, it appears that they are of a slightly different resistance than the old one. So...I have two (2) brand new sending units here, neither of which will work with the car. Slipped the old one back into the tank and gage is back working. Any else have the problem with the older stuff? Are there different sending units? Everything I see shows that they are supposed to all be the same?