71 Dodge Dart Demon question about suspension

When I removed the factory installed rear axle in me 74 Dart Sport I found it was never right from the factory when they tightened the U bolts they pulled the location pin into the plate about 3/4 to 1 inch off off of the locating hole.

Take a look at the ends of the U bolts and see if they look like about the same amount of thread is sticking down past the nuts, if the length is off this might be the problem.

Every mopar I have ever owned has the rear diff offset to the right...including my truck. I always run a 1/4 inch spacer on the left side. I was told many years ago by an old timer that it was done in conjunction with the additional leaf springs on the right rear to help the cars launch straighter under hard acceleration.

The drivetrain is offset to the right side to give more room for the driver.

When I was racing and we needed to square up the tracking of a car the best way was to:
1) Jack the car up level on jackstands.
2) mark the location of the grease fittings in the lower ball joints (L and R) on the floor. (a self leveling point laser works best for this)
3) This is the center point for a 6' diameter circle to be drawn out on the floor.
4) Connect a straight line under the car from the intersection of the two radius's at the front and the back running it back past the location of the rearend.
5) Run a square line off of that line at the leaf spring center pin locations. If you are not using SS springs you can check this dimension from where the spring hangers connect to the unibody. There is a very slight difference left to right with SS springs due to the difference in the arch.

There are several variables to take into consideration when doing this. If the car was ever wrecked the ball joint locations could be different. Locating and transferring lines has to be dead accurate otherwise the centerline will trail left or right. This is a huge PITA to do but doesn't take very long.
You can also measure from the grease fitting in the lower ball joint directly back to the leaf spring mounting pad. but if for whatever reason the b/joint locations are incorrect the rear will also be.


Since these are production vehicles and are supposed to be much better aligned there is no reason why you could not use the center of the front and rear frame ( maybe the bumper) and locate that line to the floor using it to check the square of the rear. A plumb bob from the center of the bumper would work fine.

Make sure both leafs are the same length. Measure centerbolt to front spring eye. Also check front hangers. Offset left to right is normal, but tracking should be straight.

Figured it out, there was 3/4 0f an inch different between sides, did all the measurements and everything was panning out, bumpers,frames,supports nothing was replaced ,org quarters finally measured off the rocker panels and there it was...split the different 3/8 set it up , put it back down, bounced the car multiple times, perfect measurements and now it looks normal...but why all the headaches....