The 311 is best suited for Medium/Large-bore production, Big GT, American Iron and Sedans, World Challenge Touring, Grand-Am Cup, Larger Can-Am, Sports racers and Prototypes and High-horsepower vintage, Trans-Am. American GT, Porsche Club
The 305 is designed for Medium/Large-bore production, Big GT, American Iron and Sedans, World Challenge Touring, Grand-Am Cup, Larger Can-Am, Sports racers and Prototypes and High-horsepower vintage, Trans-Am. American GT, Porsche Club
Designed for Formula cars, DSR/CSR/ Formula SAE/Radicals. OEM on Stohr Cars & West Race Cars.
Designed for lighter application Production, GT or Improved Touring cars; larger Sports racer and Formula cars