Because the front and rear joints are NEVER equal at all times, we must find a happy medium to set the pinion angle.

This is why you can't blindly follow the Mopar Chassis manual, as the section on pinion angle is just a reprint from a '68 B-body shop manual where all values were already known. What happens when you raise or lower the suspension and/or transmission, or significantly alter the power-train angle?

For example, if you used the Mopar Chassis manual to set the pinion angle of a rearend mounted higher than the transmission, the driveshaft would bind.

Please explain why the pinion should not run parallel to the transmission when the vehicle is under power? Once again, I must stress "parallel" does not mean "pointing at each other".

In addition, 2 joint driveshafts are always set up this way from the factory. If you measure a stock A,B or E body, you will find the static pinion angle is 2 degrees negative relative to the transmission center-line.