Pinoin Operating angle 73 Charger

[JonSellards84]

What is the pinion angle on a 73 Charger have installed a 69 8 3/4 underneath using a inclinometer should the vechicle weight be on the ground or is on jackstand ok also can u measure it from the pinion snubber plate and if adjustment is needed where to locate wedge plates

[Kern Dog]

?

[flyinlow]

Weight of the car should be on the suspension. I made four blocks about 6" thick out of scrap 2x12's with chocks to keep the car from rolling off. This allowed me to squeeze under the car.

I took a measurement on the driveshaft ( 4* down toward the rear axle) and removed the driveshaft to get a measurement for the pinion off the companion flange where the retainer straps bolt on (2* nose down).  4* + 2* = 6*pinion angle. Under a forward acceleration load the pinion nose should raise reducing the driveshaft/pinion angle reduce toward zero angle. I do not know what the angle is under extreme load. I have heard that 4*-7* is a good range to shoot for with the suspension under no load except the resting weight of the car.

73 Charger/ 8 3/4 axle without isolators/ Mopar HD springs four years old. This is with 2* shims between the axle housing and the spring. Thick part of the wedge toward the rear of the car.

This is the way I did it, maybe others will chime in. 

[bobs66440]

You will get a lot of opinions and debate on this subject. Every tech article I've read recommends for street cars, the pinion and the trans output shaft center lines be parallel (0 angle). The angle difference between the pinion/driveshaft and trans/driveshaft are around +2/-2 degrees respectively. The angle measurement needs to be taken in relation to the drive shaft, not the ground. The car needs to have full weight on the suspension.  Some drag racers like to have negative angle (relative to the trans) pre-set so that under hard acceleration when the pinion want to "climb" the ring gear, it brings it into alignment. Just keep in mind that u-joints are designed to work between 1-3 degrees max.

http://www.carcraft.com/howto/91758/index.html

http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html

[Chryco Psycho]

on a 73 you mayhave the rubber bushings between the springs & diff , typically we set the diff 5-7* nose down from the driveshaft so that straighten under power as the pinion climbs the ring gear