Between 1946 and 1961, the 500cc Formula 3 was an important stepping stone for drivers wanting to reach a Formula 1 career. Famous drivers included Stirling Moss, Ken Tyrrell and Bernie Ecclestone. The chassis, a lot of them John Cooper's, are very light and simple and powered by a bike engine and gearbox, such as these Norton and JAP units. Rear engined racecars would be the norm ever since. Very cool that they still run them on the track! As seen last weekend during the Historical Grand Prix at Zandvoort.