Pre-race
Prior to the 1968 race, modifications were made in the run from Maison Blanche to the pit straight, involving the installation of the first Ford chicane to slow speeds along the open pit area. The changes added around 10 seconds to a lap.
In 1968, the rules of sports car racing were changed to reduce speed. Like in Formula One, 3.0 L engines were adopted in order to reduce costs by the use of similar engines for both kinds of racing. Thus, cars with engines larger than 5.0 L were banned from the World championship and from Le Mans, which was the end for the Big Block Ford (Mk II and Mk IV) and for the Chevrolet-powered Chaparral in Le Mans. Cars with up to 5.0 L engines were still allowed to compete in the Sport category if there were at least 50 cars built. This allowed old customer cars like the Ford GT40, the Lola T70 and the Ferrari 275LM to compete against factory prototypes powered by sophisticated 3.0 L engines.
Enzo Ferrari was disappointed to have to take his P4s to the museum, and refused to compete for 1968, despite having an F1 engine. John Wyer had to retire his GT40 derived 5.7 L Mirage M1 as well. Wyer chose to dismantle his M1s and to build new GT40s on the Mirage chassis which was close enough to the GT40 to comply with homologation. Gulf GT40s received some of the improvements of the Mirage, and a significant effort was made to reduce the weight of car using high-tech materials. A large part of the body was made of a very thin polyester sheet reinforced with carbon fibre. Wyer entered 3 GT40s but the team wasn't at its best. Its fastest driver, Jacky Ickx, had broken his leg practicing for the 1968 Canadian Grand Prix, and Brian Redman was still out after breaking his arm in a crash in the 1968 Belgian Grand Prix at Spa.
The competition was between Wyer's Ford GT40 and the new 3.0 L Matra 630, Alpine A220 and Porsche 908. The new 2.0 L Alfa Romeo 33/2 were outsiders.
The Renault-Gordini V8 engine that powered the Alpine A220s was disappointing, giving no more than 300 hp (220 kW). With 350 hp (260 kW), the new 3.0 L air-cooled flat-8 that powered the Porsche 908 was underpowered in comparison to the new Matra V12, but the car was light, had very low drag and the highest top speed. Porsche was much more experienced in Le Mans and had an advantage in numbers, thus Porsche was the favorite.
With Ferrari protesting, the marque was represented only by privateers. The best Ferrari was a green 275LM entered in the Sport category by David Piper. This car was obsolete despite being seriously updated; most of its body was made of polyester/fiberglass instead of aluminium.
Two turbine-powered Howmet TXs were also entered in the prototype class.
Read more about this topic: 1968 24 Hours Of Le Mans