Myself I deal mostly with stock body cars and the eng/trans and pinion paralell line theory works good when the trans is higher then the pinion. But after reading alot of this to me on any type of very modified race car you just need to know the height of both the trans and pinion so you can take into account how to set it up since you cant just assume the trans is higher. Myself I like to make a drawing and write down all my readings so I can visualize what I need to do since as was said on some race cars you could run into alot of different setups and on some you just have to use common sense. Ron