Once you could get this supercharger option, 43% more power

In addition to building cars for Hertz, Carroll Shelby decided to treat himself, his secretary and a handful of his closest associates with a batch of specially developed GT350 Convertible's. Not offered for public sale, between four and six were made (all in different colours), the chassis numbers ranging from 6S2375 to 2380. However, whether of not 2379 and 2380 were ever completed remains a mystery. 11 GT350's were also equipped with Paxton superchargers during the 1966 model year, Paxton's Joe Granatelli having approached Shelby with the concept in early 1965. The idea was for a Paxton supercharger kit to be offered as an official option and Shelby lent Granatelli a '65 GT350 (chassis 5S425) for use as a development mule. The prototype was completed in July 1965 and Shelby was apparently bowled over by the cars performance. He went on to order 500 Paxton kits for installation by special request,