Production sports car racing was very popular throughout the post-WWII era through to the late 1970s.
Technology and performance developments throughout this period have made it clear to split up the category into three classes – 1941-1960 (Group Sa), 1961-1969 (Group Sb), and 1970-1977 (Group Sc)
The Group S categorisation is for cars built up to the specifications as laid out in the governing body’s rule book as most of the cars from the time were later developed outside their period specification, or destroyed/lost.
However, some cars from the period are now appearing and proving provenance to give them a Certificate of Description of their authenticity, therefore being eligible to receive a Group T log book. Group T is for vehicles of this kind from 1941 to 1977 with no sub-category a, b or c.