You have to use an old type of engine, without an SG crankshaft.
Like this OS


Or modify the car (my suggestion) to put in the latest type of engines and clutch systems... a Centax 2 clutch can even work of the Quattro gearbox....

Here you have an (old) picture which give you an idea what you need to do...



You can see I brought the brake disks to the inside of the bearing block, this is what you need to do, to make room for a modern "SG" type of engine....