More of my ramblings on the subject.....
The Porsche customer cars for 1978 where little different from the 935/77A but the works 935/78 was a totally way out new car with a space framed front and rear, glass fibre floor which made the car 80mm lower with a reduced roof height of 75mm.
It won at Silverstone, retired at Vallelunga and the Norsring and was retired after Le Mans where it finished 8th but was timed down the Mulsanne at 227mph - a full 5mph faster then the prototypes. This car was known as Moby Dick.
All other 935/78 were built by Joest for IMSA racing in and are also known as 935/78-81 or 935/81.
For 1979 there was no factory cars but IMSA had decreed that all twin turbo cars would carry 40Kg of ballast. Porsche developed a slightly larger engine with a single turbo known as 935/79. The Interscope team won at Daytona.
Kremer had upadated the K2 in 1978 but for 1979 bought out the K3 with 100 changes, including an air to air intercooler, moved oil cooler and fuel tank, bodywork weighing 30Kg and a roll cage that also acted as the front suspension pick up points. It was 1% more efficient, easier to maintain and run. Two versions wer available, large engine single turbo for IMSA and smaller engine twin turbo for Gp5. A Gp5 K3 won Le Mans in 1979.
Some were still running at Le Mans in 1982 in the IMSA class with revised bodywork.
The cars that Kremer supplied in 1980 were known as 935K3/80 and are sometimes confused with the 935/80 which they are not. Also kits and parts could be supplied to customers to convert to K3 standard. The 935/80, more commonly called the 935B2, was built by Porsche for Georg Loos and was based on the 935/77 with lightweight body and upgraded suspension.
For 1980 Joest had buillt his own version also based around the 935/77 and this was know as the 935J. One won at Daytona that year. He also supplied other teams including Vegla who ran a car at Le Mans in 1981 finishing 10th. This car is sometimes called a K2 but I do not know why because it isn't.
More later, Ian