I need to buy a sending unit for my 70 Cuda, (340ci engine).

The last one I bought I got from Classic Industries and it appears to be non-functional after I installed it. I verified the gauge is working properly and the tank has good ground. When measuring the resistance of the sending unit I get 18Mohm reading which says the unit is not working correctly.

Given that I don't want to have to replace the unit a third time, I am looking for a recommendation on where to buy one of these that is of better quality.

I understand with the exception of NOS all the aftermarket ones are not that good but I at least want to buy one that is functional and is reasonably accurate.

Also, is it possible to swap out the sending unit without having to drop the tank?