In the 4x4 world they have to make all kinds of compromise to get the driveshaft to be acceptable. Turning that pinion down probably will make the angle to extreme for the u joint to handle, I had a jacked up ramcharger in here where they made them parralell but it ate u joints like crazy as the joints were maxing out and hitting themselves, we made the angle "wrong" and the vibration went away and so far no more joints gettin wasted. It is not ideal but just has to be done that way no way around it on a short wheel base jacked up rig. I think he could have gone with a CV shaft but it would have been more money than the truck was worth.

On leaf spring street cars I shoot for parralell or even put the pinion pointing 1 -2 degrees less than the engine/trans center. I don't know if that is ideal but has worked for me to keep vibration away and long u joint life. If it is powerful enough to twist the spring that bad I add a leaf, cal trac, clamp the front segment or even gasp! Pinion snubber.


I confess I do not do much race car stuff, no race tracks around here.