it is possible you still have air pockets in the water jackets and coolant system. It will take several drives before you burp all of the air out. Also check the spark plugs and timing. If it is too retarded it will over heat. Also if it is running too lean it will over heat.
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.