I just found this old post. I happen to have same kind of FIM radiator in my 1977 Pantera, which I´m working on at the moment. Did you keep on using your FIM radiator?
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.