ZDDP is sold as an engine break in additive by most of the hot rod shops. I happen to buy mine from Summit Racing on line. I buy the Comp Cams break in additive. It costs about $12 per bottle and I use one bottle with every oil change. Good piece of mind.
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.