Any vintage Fiat or Alfa dealer. The actual sender won't interchange but the mfgr is the same. Some floats are sold plastic, some are hollow. They interchange but your gauge calibration may move. Careful bending of the hardened steel wire arm can readjust your gauge.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.