Pinion angle ??

[71scamp78]

What would the stock yoke angle be on a 70 darr with a 8.75 diff. I'm putting a new rear end in car and need some of the factory specs. The guy that is doing the rear end for needs some specs. Obviously my car is at home and not his shop and my trans isn't in car either. He needs to weld on the new perches but needs some factory numbers so he can set it up right. I know it's better to do with the rear in the car but that's not an option right now. Thanks

 

[Scody21]

What would the stock yoke angle be on a 70 darr with a 8.75 diff. I'm putting a new rear end in car and need some of the factory specs. The guy that is doing the rear end for needs some specs. Obviously my car is at home and not his shop and my trans isn't in car either. He needs to weld on the new perches but needs some factory numbers so he can set it up right. I know it's better to do with the rear in the car but that's not an option right now. Thanks

Don’t do it. Wait until everything is together to set the angle. You can take the housing set on the perches on the springs, and bolt into the car for moving purposes. You want all of the weight in the car, and the car on a 4 post lift at ride height to set correctly.

 

[33IMP]

Dr. Diff says factory setting was pinion 5° up, from the pads. When you put it together, depending on what you are doing with it, you want it assembled 2° to 7° down , from the driveshaft.
There are obviously multiple different angle shims that can be used to dial the angle in correctly, after assembly.

 

[mopowers]

Per Dr Diff:

"If you want to duplicate the stock A-body pinion angle, weld the perches at 43" on center. The pinion should angle upward 5 degrees when the perches are level with the ground."

 

[pishta]

Only way your going to get it correct is to mount it up with the perches not welded in and set it on the ground. Rotate the pinion down 2-7 in relation to the trans output shaft (or valve cover top with a level) so when it wraps up under acceleration, it will be close to 0 in relation to the output shaft. If you got stiff springs, youll want the smaller end of the range (-2). then you can scribe a line across the housing and the perches and take it in to get welded.

 

[oldkimmer]

Also I will add that if u weld on the perches b4 hand the diff may be over farther to 1 side than the other. Then the tires won’t be centred in the wheel tubs. A couple cars I have did were out by an inch or so. Kim