on cars modified for racing, the tachometer is usually rotated from its usual position (the usual position is with the numbers upright) and oriented with the optimal rpm positioned at 12-o'clock. This, to enable the driver to visually check through peripheral vision when to shift - it is easy to check visually when the needle is at the 12-o'clock position. This "optimal" point is usually the power peak of the engine.

on this Skyline (and other serious sports/race cars), the tach is designed with this in mind - note that the numbers are upright.