Adding some more info from the Luigi Fusi, All cars from 1910!
The 33/2 Litres Sports prototypes car:
Work on the type 105.33, which was intended to compete in Sports Prototypes category races started in September 1964.
The first car was ready by the end of 1965 with a provisional TZ2 engine. Built by the experimental department at Portello it was subsequently sent to Autodelta where further units were made in various tuning stages and tested by the experimental departments of the company.
In the general layout of this model, with its new V8 engine at 90 degrees mounted at the rear, which forms an integral unit with the gearbox and independent rear axles, of particular interest is the chassi based on aeronautic design. etc.
Manager of the Alfa Romeo Designs and Experiments Department, was at that time Dr. Ing. Orazio Satta Puliga, and indeed on the lists of his Projects in 1967 the 33/2 Litri model Sport Prototypes class is listed.. page 827.
I think this is very consistent with what has been said here before that Alfa themselves were the starters of the Tipo 33 Project, and then handed the car over to Autodelta for further development!