There is one subject, as far as racing cars are concerned, that we can ignore, that's the position of the engine. Sure, in those derived from standard cars it's quite clear, with the exception of the rare case where the engine has been transplanted from the front to the rear, regardless of whether straight- or transverse mounted (picture 1). Indeed, this is mostly also how the standard models are developed (picture 2).
These examples do however, show the direction of Ferdinand Porsche's mid-engine design for Auto Union from the 1930s (picture 3). Strangely enough, the slightly higher amount of weight on the rear axle was deliberate and promised success. So, if one had the choice, the engine was placed in front of the rear axle.
Nowadays, together with the monocoque, it has even become a supporting part, very different from the standard car, where the engine-mountings have become softer. The rear axle is bolted onto the gearbox or onto the integrated final drive, the front axle is bolted onto the front part of the monocoque directly behind the nose.
Oh yes, the gearbox. You can see one here and, you can see that:
It has to battle against a very low centre of gravity.
It may not protrude to the rear as much as a standard gearbox.
The centre of gravity in fact, appears to be the most important thing in a genuine racing car. Can you imagine, that it lies just below an imaginary connecting line between the front- and rear wheel centres, and that a minimum measurement is part of the regulations? For this reason alone, the flywheel cannot be protruding. This is where a, far removed from the standard, multi-disc clutch with a particularly small diameter is installed.
You can imagine what a challenge it is, e.g., to build a Formula 1 vehicle, whose performance is expressed in horsepower and its weight in kilogram. The changing amount of fuel in the tank during the race, plays a completely different role than in the approx. twice as heavy compact-car class. Positioned in the middle, the changes have the smallest affect. Just recently, even the weight of the driver (unfortunately in Formula-1 it's men only) is taken into consideration. 04/14