Reply to "Fuel Sending Unit"

A stock Ford EFI fuel pump will fit on the end of a stock sender if you're willing to do some adaption. An electric pump needs two extra sealed wire connectors not present on either of the senders (4 total), and the bottom end of the tube needs to be shortened by the length of the pump & its filter. Then you need a secure hose connection and a mechanical support for the pump.
To test the idea, I added a TBI electric pump (identical dimensions to an EFI pump) to our OEM Pantera sender. TBI pumps only put out 10-12 psi and can be regulated down to 8 psi for carbs without pump damage, while EFI pumps cannot. The finished assembly fits thru the stock tank opening and works fine as a backup fuel supply on my carbureted 351C. The advantage of an in-tank pump are: better protection, no suction problems & no vapor lock, with quiet operation compared to outside mounts. Note this was a STOCK Ford pump; oversized aftermarket pumps likely won't fit thru the opening. There's room on a Pantera sender top for the two extra sealed wire connections; not sure about the FIAT sender. Written up in the POCA Newsletter a couple of years ago & still working as of today.
To fit the X-19 sender in a carbureted Pantera, be prepared to chop off or sharply bend the two hose bibs for engine cover clearance. Smooth bends are better for good fuel flow. When you alter the hose bibs & install, maintain the stock clocking so the float arm fits the Pantera tank baffling, while lining up the bolt holes.