The original master cylinder has a diameter of 24 mm or +/- 15/16'' and is common with the Ferrari 308.
It is certain that as with all semi-industrial or semi-artisanal cars, it's as you want, De Tomaso used parts from existing mass-market models, this is what made it possible to obtain a very low price for performance equivalent to that of Ferrari, Maserati, Lamborghini and other Porsches of the time. The engine is the most significant, +/- 300 hp at the time in Europe was reserved for very expensive brands.