Check the ground strap from the ZF to the chassis. Make sure that it is in good condition (no broken strands), and that the connections are clean and tight.
FWIW, I have 111k miles on my original starter and the engine cranks and starts fine hot or cold.
John
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.