Andy Granatelli of STP fame was a signifigant contributor to the early Studebaker Avanti legacy
- He sold his supercharger business to Studebaker
, which owned half of a company named Chemical Compounds. He took over as head of the firm, changed its name to STP, and hiked sales from $1.9 million per year to $100 million in nine years. He dressed himself and crew in uniforms covered with STP decals. The STP trademark became one of the most familiar brands in advertising history. Sherwood Egbert
assigned Granatelli the task of putting the Avanti through its paces. Granatelli set two major American class C records: a two-way flying mile record of 168.15 mph, and a standing start mile record of 92.03 mph. Two new engines, developed through the efforts of the Granatelli brothers, were known as the R3 and the R4. Buoyed by these new engines, Studebaker tried for performance records in the summer and fall of 1963. To add some excitement, the Granatellis put together a mind-boggling R5 Avanti, known as the Due Cento
equipped with twin superchargers.