Porsche 956/962 design differences towards the end of the 956/962 dominance

Porsche 956/962 design differences towards the end of the 956/962 dominance.

This first photo on the right is a Group C 956, the middle is a IMSA 962 and on the left is an IMSA 962. The Group C on the right and IMSA car on the left are both long tail designed, the middle IMSA car is a modified bodywork 962, you can see it follows the Short tail design. The bodywork/engine covers on the IMSA car on the left and the Group C car on the right extend out under the wings. The middle IMSA car the engine cover stops short of the dual plain wing on it, but the sides of the car continue to the end of the wing. 

The second photo is of the Group C 962 and is a short tail design, the bodywork/engine cover ends just in front of the rear wing and the wing has its own center support structure. 

What the short tail designs did was use the rear wing to assist pulling the air out from under the car creating more down force. 

The third photo is a Group C 962 that has the long tail bodywork/engine cover on it. 

The Miller High Life Porsche 962 from Jim Busby Racing is considered to be the fastest 962 ever built. One of the problems with the Porsche 962 models was they were still being built with aluminum tubs while the competition was using Carbon Fiber/Kevlar to build their tubs, the competition was able to build lighter cars and design where to put the weight to meet the series minimum weight requirements. The other issue was the Porsche engine designs were long in tooth where the competition was developing new engines that could make more power, the IMSA cars used a production car based engine per the rules that was completely air cooled, the Group C cars were using the first Indy car engine that Porsche had designed, while the Group C cars were getting an engine designed from the ground up to be a racing engine with water cooled heads and air cooled cylinders it was also getting long in tooth and was at the end of its development compared to the newer designs from the other manufactures.

It would have cost Porsche millions of dollars to design a new engine from the ground up to be competitive with the other manufactures and Porsche decided that was not cost effective.