You will have to open the mounting tab. By that I mean you will have to bent it to slide the mount in then use the shims, those large spacers to take up the space. You could also loosen the motor mount bolts, the single bolts connecting the upper and lower mounts with the rubber isolator in-betwwen, to shift the motor/trans assembly the 3/8th inch you need.
It must have been a pretty sever impact that they had to replace the trans mount. They would have had to replace the rear frame members in the impact area.
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.