If you want to keep whitin FIA Homologation rules, 1220Kg is the limit.
Se bottom of page #2:
https://historicdb.fia.com/sit...ber_3047_group_b.pdf
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.