This may stir up some debate because I know there's a lot of opinions out there....
How do you guys set your pinion angles? (OK all you fast guys with no suspension can ignore this one )
I've seen people swear that it needs to be set at some particular angle, usually pointed down slightly. Then there's the camp that lines it up with the tranny angle - which could mean pointing it up.
Here's how I see it:
If you're running ladders or a 4 link, the rear end assembly can be seen as a solid peice with very little rotation. Hence, the pinion angle is not going to change dramatically like it would with leaf springs due to spring wrap-up. Plus, looking at it as a block box, the rotational torque load on the ladder bars and the car is the same regardless of where the pinion comes into the box.
U-joints are designed to be run in parallel. Hence, the u-joints are going to be happiest, and have the least amount of binding, if the pinion is parallel to the transmission. This means that if your engine is pointed down, the pinion should be pointed down at the same angle. Likewise, if the engine is pointing up, the pinion will be pointed up at the same angle.
I put the rear end at ride height and set the point angle to match the tranny angle.
I figure that this is the easiest on my u-joints, which is easiest on me...
Perry