A-Production racecars are generally referred to as the “Big American Iron” 1960s to early 1970s ground pounders with “big bore” V8 engines such as 427 cubic inch Cobras and other American super-muscle cars with 350-400+...
D-Production racecars are commonly mid-1950s to late 1960s 1.5 liter to 2.0 liter British, European or Japanese sportscars such as MGBs, Triumph TR6s, Alfa Romeo Giulettas, Datsun 2000s, Fiat 124s, select Jaguars, Austin Healey 3000s,...
C-Production racecars generally include 2-liter to 2.5 liter Porsche 911s, Porsche 914s, Ginettas, Datsun 240 Zs, Ford Escorts with Cosworth and/or BDA twincam engines and other “medium bore Production” cars, mostly British, European or Japanese....