Hello all. Years ago when scrounging parts for my RR I found an overall nice Bbody Dana but the mounts had been relocated. I didn’t have a problem with that. I bought some new mounts, located them side to side but merely estimated the angle in relation to the pinion. The car has been together for a while but suffered from some serious wheelhop with little effort. Trying out a couple softwares that total your angles and tell you where you have issues, I realized that rotating my diff angle 6* put the whole drive line in sync. I bought some 6* wedges and it worked but I do not like them in there. I had to but longer u-bolts and those size wedges actually lowered the rear.

So, on to the question. As a check before I remove the rear, cut off the mounts and weld on new ones at the new angle and refinish everything as nice as it looks now, does someone have the factory angle between the pinion and the mount?

You could have bought 6 degree wedge shims from a 4x4 source and those would only have raised the axle above the spring by about a 1/4" at the most, an you would not have needed longer u bolts with the shims. Get the shims that the center bolt passes through, it helps keep them in place better (you will probably need new center bolts).

Be aware, your current set up is only 6 degrees or axle rotation off. Your axle tube is only 3" in diameter, 6 degrees is not very much axle rotation.

You have the correct positions of the spring perches with your 6 degree wedges right now. Build a jig that allows the rear end to sit on both 6" wedges. Be sure you mark the hole for the top of the center bolt and add that center bolt to the jig. Then with the wedges sitting on the center bolts for location, extend that jig out so you can set the pinion yoke on top of. If your wedges actually lift the rear end, and you don't want that, you will need to adjust the pinion height lower by the same amount you want to take away from the height the wedges added between the axle and the jig. If the wedges added 2" between the axle and where the wedge sits on the spring, then the place the pinion sits on the jig will be 2" lower then it would sit on the wedges.

Then you can remove the current saddles and wedges from the axle, clean up the rear end, and set the new saddles on the jig's center bolts, then set the pinion on the top of the jig, and weld the saddles to the axle.

The factory mounts are pretty close to pointing the pinion 5 degrees up. The spring itself has a nose down angle where the housing bolts. best way is to leave the perches loose. Bolt the housing in on the loose perches. snug it up. Then pap th enose of the pinion with a soft face hammer to get the angle where you want it. You may also want to offset the housing right or left a bit to center the wheels in the wheel house. Mopars are notorius for the wheel houses to be off right to left. Usually doesn't take much. A 1/4"-3/8" can make a world of difference in clearance.
Doug

Pull your axle, lay the axle perches down on to a perfectly horizontal surface. Check the pinion angle. Add 6 degrees to it.
Now you know what angle to mount your new perches.

Sandy - I ended up fine tuning my driveline angles with a 2* wedge. (68 Hemi Runner, Auto, 4:10 D60) Fairly certain the spring mounts were not relocated by previous owner. I can check the offset of the mounts to the snubber pad on mine tonight with a digital level for comparison to your D60. Assuming the snubber mounting pad is machined parallel to the pinion shaft axis??

68jim

Sandy - I measured my set up last night and would agree with Doug about the 5 degree offset. I had to eye ball the spring mounts since I was not going to disassemble the springs. I was getting numbers in the 4.6 to 4.8 (ish) range and the axle housing did not have scars from anything cut off and rewelded.

68jim

The reason being of 5 degrees up is the way the springs fit to the hanger mounts. The spring is designed to be relatively flat and the front eye is lower than the back mount, like a jacked up car looks, a straight spring holds the car better in corners. The S/S springs with big arch is for drag racing only. One thing about the SS spring, never weld both perchs where they sit on the spring. Tack one side then remove housing then tack other at same degree, re check your measurements and weld up. Then when bolting the u-bolts one side will pull the spring up to set the spring preload Chrysler engineers designed into them.