Group 4 (motorsport)

Did You Know?

• The Group 4 regulations served as the basis for the World Rally Championships until replaced by Group B.
• For rallying in the mid-1970s to early 1980s, 400 identical cars were required for Group 4 homologation.

Production requirements

Prior to 1966, Group 4 covered Sports Cars complying with FIA Appendix C, as well as modified Series Touring Cars, Improved Touring Cars, and Grand Touring Cars that exceeded Group 1, Group 2, or Group 3 limits. Announced in October 1964, a major overhaul from 1966 required Group 4 Sports Cars to have a minimum production of 50 units in 12 consecutive months and full road equipment. This led to the homologation of the Shelby 427 Cobra Mk3, Ford GT40 Mk1, and Ferrari 250 LM in early 1966, though the Cobra and Ferrari faced controversy. After Ford's 1967 Le Mans win, the FIA imposed a 5000cc engine limit for 1968 and allowed the Lola T70's homologation by counting earlier open-top cars. In April 1968, the minimum production dropped to 25 units for 1969, prompting Porsche to build 25 Porsche 917s (homologated April 1969) and Ferrari to produce the Ferrari 512S (January 1970). These cars were essentially Group 6 Prototypes with 5-liter engines instead of 3 liters. For 1969, Appendix J defined Group 4 as sports cars requiring 25 units in 12 months. In 1970, the limited-production sports car category was renamed Group 5, and Group 4 became the class for special grand touring cars with a minimum of 500 units. By 1971, Group 4 remained special grand touring cars (500 units). In 1976, the production requirement was reduced to 400 units in 24 months.

Sports car racing

In 1966 and 1967, Group 4 Sports Cars were primarily sold to privateers and played a supporting role to Group 6 prototypes. Factory prototypes like the 7.0L Ford GT40 Mk.II and Mk.IV competed for outright wins, while 4.7L GT40 Mk I entries vied for Group 4 class victories. The two categories contested separate championships: Group 6 for the International Championship for Sports-Prototypes, and Group 4 for the International Championship for Sports Cars. With larger engines, the simpler Group 4 cars became contenders for overall wins; an updated Ford GT40 Mk.I won Le Mans in 1968 and 1969. Porsche developed the 917 with a 25-car run, and Ferrari, with Fiat's help, produced the Ferrari 512S. In 1970, Group 4 Sports Cars were renamed Group 5, and a new Group 4 Special Grand Touring category emerged, contested by cars like the Ferrari 365 GTB/4 Daytona, Porsche 911 Carrera RS, and De Tomaso Pantera.

List of FIA Group 4 homologated cars

Cars could be homologated for Group 4 as variants of Group 3 cars using a "100-off rule" before 1976, which required production of 100 "bolt-on option kits" rather than modified cars. This rule was deleted after 1975, with approved components banned from the end of 1977. An example is the Group 4 16-valve TR7, whose multi-valve head from the Dolomite Sprint was approved for Group 4 on 1 October 1975 and reapproved on 1 February 1978 after about 60 TR7 Sprints were built in 1977.