So I know this thread is a few years old but just wanted to thank everyone for the info herein, and add my 2 cents.

Needed a sending unit for my 53, and wanted to use the new replacement unit from Kanters, but was told they are on indefinite back order. After reading through this thread I decided to take a chance on the FG97a from Spectre. It was only like $60.00 at Amazon!Had to do a tiny amount of trimming to the plate on the unit but otherwise it was fairly straight forward.

Haven't run it down to empty yet, but it seems to be registering about right so far.More concerned about it registering empty correctly than full. If I run into any problems down the road I will update.

I have nothing technical to add, just wanted to say it looks like you got a heck of a bargain on your Packard!Looks like nice old ride- enjoy!