fastest recorded TR8 (KPH 574V) at MIRA. Motorsports British Leyland ran a team of TR7s in rally competitions from 1976 to 1980. These cars initially used the 16-valve Dolomite Sprint engine and later switched to the Rover V8 engine (before the introduction of the TR8, so dubbed "TR7 V8"). They were reasonably successful on tarmac events but were less successful on gravel sections. The most successful driver of these cars was Tony Pond. John Buffum won the SCCA PRO Rally Championship from 1977 to 1980 driving TR7 and TR7 V8 cars. The TR7-V8 models continue to be successful in classic rallying events. Group 44 ran two TR8 cars in TransAm and IMSA Championship from 1978 to 1981, while in Canada a third IMSA car was run with support of JRT Canada and was raced until 1985. The Group 44 effort lead to many wins of the TR8 in USA and was the most successful campaign of this type of car. The fastest road race TR7 was built by RMP Motors in Canada, winning two back to back GT1 championships in 2012–13. The 16-valve engined TR7 rally car was homologated for group 4 in October 1975, well before any 16-valve TR7 Sprints are known to have been produced. This was possible at the time using the "100-off rule", as John Davenport called it, in the FIA's appendix J to the International Sporting Code 1975. This 100-off rule described a list of "Optional equipment which may be recognized with a minimum production of 100 units per year to equip 100 cars" and requirements for their use. However, it did not require that any cars actually be so equipped, just that 100 of the "bolt-on option kits" be produced, listed, and made available for sale. As well as alternative cylinder heads with different numbers of cams and valves, this list of optional equipment also included many other engine, suspension, and transmission components, and so covered the use of the 4-speed, close-ratio gearbox and overdrive from the Triumph Dolomite Sprint (the heavy duty axle from the 5-speed TR7 was initially homologated for group 3 by another, less clear, route, though re-homologated later, presumably on production of 5-speed TR7s). Further modifications, including the larger front brakes and rear disk brakes, were covered as "Optional equipment which may be recognized without a minimum production". In 1975, Appendix J listed yet more modifications allowed, with restrictions, to