[toddoky]

The absolute degree of the engine/trans inclination angle and the pinion angle is primarily important as to how it affects the U-joint working angles, which you cannot calculate without also measuring the angle of the driveshaft (actual part or a mock-up of one). You can have engine/trans and pinion angles that match each other exactly and still have excessive U-joint working angles due to extreme elevation differences between the components (i.e. lowered vehicles).