This 3D-track was original made for Grand Prix Legends by Papyrus. It was converted for GTR2 by Sunalp2 and later enhanced by NeelJ. It was ported to Assetto Corsa by Rainmaker.
https://www.mediafire.com/file/72ywc26agrxd8of/Mexico_GP_1967_v1.0_by_Rainmaker.7z/file