Most 550 RS Spyder enjoyed a long career of racing well into the early 60's. With the on-going development of the 547 engine, crafty mechanics were able to crank up the power of the original engine with new parts from the RSK and increased displacement to about 1700 cc. This was especially true for hillclimb prepared cars. Extra lightweighting by drilling the frame was commonplace to squeeze every bit of performance from the 550.
The cars that raced later in the 50's also benefited from rapidly improving tire technology. In 1958, synthetic rubber compounds with nylon bias-ply, such as the Dunlop R5, appeared on the tracks. They greatly improved grip and thermal resistance compared to their natural rubber predececors.
One fine example was Roger Ward's modified 550 that finished 2nd at the 1960 Pikes Peak hillclimb and raced in the USAC championship.
The cars that raced later in the 50's also benefited from rapidly improving tire technology. In 1958, synthetic rubber compounds with nylon bias-ply, such as the Dunlop R5, appeared on the tracks. They greatly improved grip and thermal resistance compared to their natural rubber predececors.
One fine example was Roger Ward's modified 550 that finished 2nd at the 1960 Pikes Peak hillclimb and raced in the USAC championship.
