Assuming the indicated timing is correct, I think you need an additional 8* of timing, or use George's method of setting timing where you adjust the initial timing to produce the highest RPM, drive it, and back off a degree or 2 at a time until any detonation or pinging disappears. That should make a significant difference in idle quality and drivability. Good luck..
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.