For drag racing I prefer the pinion centered in the car as well as the engine. The drive shaft should have a slightly down angle at the transmission and a 3 degree pinion down angle on the rear end. The intake manifold should set level. Some prefer it level at rest, others go for level without about an inch up travel on the front suspension to simulate the launch at lift....I usually set my engine level at idle. Never have had much trouble with it that way. Some like the engine a bit nose down at rest to maintain fuel level in the bowls higher when the car is going down the track. Don't think it's really an issue though.