In 1966, the regulations allow the increase in the displacement of Formula 1 to 3 liters.

Cooper equips the very first monocoque chassis with Maserati's Tipo 9 engine, a V12 derived from the 250F, which develops 340 hp then 360 hp for 2989 cm3 of displacement.

The T81, thus equipped, will allow honest performances with 2 victories in GP between 1966 and 1967, several podiums and a third place for the constructors in 1966.

John Surtees and Jochen Rindt were the most brilliant drivers at the wheel of this F1.