Pinion angle, stock and recommended with SS springs.

[Ol'forest]

Yep I known this has been asked many times, but can't seem to find a definitive answer.
Firstly if I was to weld the perches on in the factory location, angle, what angle would the pinion be relative to perches? My 8 3/4 is out of a truck, and the angle on that is irrelevant but its a very steep pinion up angle relative to the spring perches. I could weld them same as the 7 1/4 in my car now but plan on swapping in RH SS springs sometime. I will consider using wedges for any fine adjustment later, but would prefer to do out of the car as it would be a PIA to get a welder to tack in position in my immobile Duster. While we are at it the perches have a round and a square hole at each end, any significance to these?

 

[33IMP]

I do not know what the factory angle is between the pinion and the spring pad. Sorry.
I do know that when i swapped to superstock springs, with my stock spring pads, i had to add 3° wedges to get the pinion angle where i wanted it. (Somewhere around 5-7 degrees down, dont remember exactly. )
My car had WAY too much rearend lift with the stock springs, the swap to ss was to help with that problem.

 

[pishta]

you want it to wrap up to a zero offset during acceleration so run it a few degrees under the output shaft deflection. if your zero on the trans end, then put the pinion down 5 on a stiff SS spring, up to 7 on a softer spring. you actually want a little offset on cruise to extend the life of the U-joints with a little rotation.

 

[crackedback]

Factory angle is 5* nose up with perches level on an A body.

My 2 cents. If you are welding them on, mock it up in the car, fully loaded and set it properly with the trans output. Tack in place, pull and finish welding them up. No shims required to get it where you want using the factory or WAG approach.

 

[Outsder]

For a performance car, put it together, eng & trans, and on the ground with the springs loaded. Adjust pinion to 3 deg down. If you don't want to weld under the car, mark the housing/pads with a felt pen, pull it and then weld it.

 

[cjx]

I swapped in a 8 3/4 out of a 62 Plymouth, when I checked the pinion angle on the 7 1/4 that was coming out it was 9 degrees. I'm using Cal Tracs bars so not worried about wrap

 

[512Stroker]

Yep I known this has been asked many times, but can't seem to find a definitive answer.
Firstly if I was to weld the perches on in the factory location, angle, what angle would the pinion be relative to perches? My 8 3/4 is out of a truck, and the angle on that is irrelevant but its a very steep pinion up angle relative to the spring perches. I could weld them same as the 7 1/4 in my car now but plan on swapping in RH SS springs sometime. I will consider using wedges for any fine adjustment later, but would prefer to do out of the car as it would be a PIA to get a welder to tack in position in my immobile Duster. While we are at it the perches have a round and a square hole at each end, any significance to these?

My 67 Barracuda 340, 727 with an 8 3/4 has, street application, 2* positive at the trans output shaft and 2.5* negative at the rear end drive shaft yoke - no issues. After I installed new ESPO springs I had to add a shim at the spring perch to correct the angle.

 

[oldkimmer]

-5* lower on a drag car. -2-3 on a street car that is basically a cruiser. That is lower than the trans angle. Kim