I have always used the Valvoline 20W50 race oil. It has High zinc and phosphorus formula for extreme anti-wear protection. Stock motor. No problems.
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.