The May 1974 issue of Road and Track magazine, page 48, quotes Peter Revson that the Holley carburetor installed in the GTS Pantera was part no. R4777AAA.
There are a few other references in other books and periodicals, but the information which confirmed to me which carburetor was installed has been based upon testimonial provided by owners, right here via these forums.
In the absence of a manufacturer that is in business, buyers, writers, businesses, and agencies are welcome to inquire with Pantera International for verification of various information. We provide such verification on a regular basis, mostly to assist owners in dealing with registration and inspection issues.
I am however disappointed that neither Isabella nor Santiago considered this international club for keeping the production information, instead it was trusted to the keeping of a private individual in Switzerland ... who charges owners more than a nominal fee for copies of documentation ... much more than what Kevin Marti charges.