I agree with the above comments that the standard Mopar fuel gage will looking for a sending unit with an 10 - 85 ohm range. So these units will probably need to work with a special gage calibrated for the sending unit. That's okay.
Don't be too concerned with linearity at the "empty" end. On my 67 Barracuda, the first 3 gallons do not count. Then somewhere between 3 and 4 gallons, the suction tube gets completely covered with fuel. Before that, you're just sucking air.
What bothers me is that these units must come in from top of the tank. On the gas tanks that I have dealt with, the top of the tank is firmly mounted (with a rubber pad) right against the bottom of trunk sheet metal. So it seems like you would have to rig up a 3/4" spacer to lower the whole tank to allow this to fit. I personally would not drill a hole in the bottom of the trunk.
