In this mont's GT Porsche there is an article about the twin turbocharged flat six engine that was used in the 956 Group C car. It's like the one about the TAG/McLaren Turbo V6 under the "Mezger's Masterpieces" section. This engine made it's debut in the 935/78 "Moby Dick" and was also used in the 936 before it finally ended up in the 956 Group C. It's not the same engine as the one in the 962, as that was fully water cooled, whereas the 956' engine had an aircooled block and watercooled cylinder heads.