Least Shoddy Fuel Sending Unit?

Most of this info has been covered before,so I'll briefly go over relevant facts about original sending units. In the mid sixties to the early seventies the part number was 2421493. From around 1973 to 1975 or early 1976 the number was changed to 3621515. Then Chrysler changed the number to 4051004. When they went to the newest number, the float was plastic. I recall seeing a Chrysler memo telling why they changed to plastic floats. They said because of brass corrosion caused by small amounts of moisture in the fuel they changed floats to plastic.