brought manufacturers back to the sport, it was again Porsche - with its 956 & 962 Group C line - that continued their domination of the sport. For 1986, the World Endurance Championship became the World Sports-Prototype Championship. Although the Group C formula was a success, with regular crowds of 50,000 to 70,000 at WSC events (a modern Grand Prix in Europe will have similar crowds), and upwards of 350,000 at the 24 hours of Le Mans, the FIA introduced new rules for 1991 at the behest of FIA vice president Bernie Ecclestone; 750 kg machines with contemporary normally aspirated engines, which were purpose-built 3500cc racing units. The new classification, known as Group C Category 1, was designed to mandate Formula One engines. Although power was generally less than existing Group C cars (around 650 bhp compared to around 750 bhp upwards) the new cars are considered to be among the quickest sportscars ever. However, the take up of these new regulations was slow and only a handful of Category 1 cars were ready for the 1991 season. Consequently, the FIA also allowed cars complying with pre-1991 Group C rules to contest the championship (as Group C Category 2 cars) during the one transitional year. They were however seriously handicapped in terms of weight, fuel allocation and grid positions. For 1991 the championship took on yet another new name, the FIA Sportscar World Championship and the new 3.5 litre rules took full effect for the 1992 championship with the old Group C cars no longer included. 1993 demise The new generation of WSC racing engines, with the stated intent of cost reduction and improved competition, quickly proved highly suspect. Costs rose massively as works teams developed cars capable of qualifying around halfway up a Formula 1 grid, despite weighing some 200 kg more. Manufacturers again abandoned the sportscar series, realising they now had an engine suitable for F1. In particular, Mercedes and Peugeot elected to either concentrate on or move solely to F1. The more exotic engines were unaffordable for teams like Spice and ADA, thus after the manufacturers left the top class of sportscar racing, the series essentially collapsed. A lack of entries meant the 1993 season was cancelled before the first race. In 1994, the World Sportscar title would return, this time in the hands of the International Motor Sports Association in North America for use in the