Examine the intake manifold for a crack or a point at which oil can enter.
The Ford manifolds have pipe plugs into the exhaust cross over.
The Edelbrock may have them too.
You are looking in the wrong places.
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.