All right, could I have some input on guiding me through checking pinion angle. When I had the 8 3/4 set up in my Dakota I dropped it off at the machine shop to have new perches welded on the tubes. I pretty much assumed that it was done right, but would prefer to double check it myself. I need to get a set of lowering blocks and need to find out what pinion angle, if any, shims I will need.
Thanks,
Shawn

You have to install the lowering blocks first. Next you find a way to get to the shaft with all the vehicles weight on the wheels, ramps work good if you don't have access to an alignment rack type lift. Next you put something on the front seat that weighs the same as you (sand bags). Next you check the front u-joint angle, must be 3 to 5 degrees, shaft down. Next check the rear u-joint, must match the front angle, but pinion down. The biggest pain in the azz is every change made to the rear angle (perch shims) changes the front angle. Note: In many cases the transmission mount will need shiming and in some cases I have had to lower the engine (modify motor mounts). If you can get both angles to match at 3 degrees (street driven) you will be very happy with the outcome.

Here we go again. I would suggest doing a search on Pinion Angle.

Make the pinion parallel to the transmission as a base line, then roll the pinion downward X degrees and weld/shim your perches. X is your desired pinion angle.

The other method is a hit or miss short cut.

In fact, I just corrected a vibration caused by someone who set pinion angle "the other way".

Ideally, when the car is under power, the pinion centerline should become parallel to the transmission centerline (2 joint driveshaft). I don't understand how anyone can continually argue with this.