I just installed a Ford 9" rear in a 1983 Jeep CJ7. I have 4" springs, 1" 3/8 shackles, and cv drive shafts. I will be running it spring under. Before I weld on the new spring perches, I was wondering what an acceptable pinion angle would be?
Thanks

angle will differ depending on your wheelbase, essentially want the pinion to be pointing at the output shaft of the transfer case. i am putting a 9" in my yj, and will wait until my crawlbox and axle are mocked up to tack on the perches.

Does 18 to 20 degrees seem like too much rear pinion angle? It's the same as my drive shaft angle. Keep in mind I do have cv shafts.
Thanks

angle will differ depending on your wheelbase, essentially want the pinion to be pointing at the output shaft of the transfer case. i am putting a 9" in my yj, and will wait until my crawlbox and axle are mocked up to tack on the perches.

X2, there is no cookbook angle that will work, you should tip the pinion down approx 2 degrees from a direct shot at the T-case to allow for loading during accel.

Install the axle without welding the perches on and loosley tighten the u-bolts. Keep in mind that when you rotate the pumpkin, it will raise the yoke in relation to the ground which will reduce the driveshaft rear u-joint ange.

Mock it up, tack or mark the perch locations and burn em in.

I agree. The only way you will get it right for your rig is to mock up the axle under the Jeep. I could tell you what pinion angle works for me, but it may not work for you. Every vehicle is different and I would hate to see you weld your perches on with the pinion set at an angle your were told to set it at from a 4x4 board and then find out that angle won't work for your vehicle.

Thanks to all !

Does 18 to 20 degrees seem like too much rear pinion angle? It's the same as my drive shaft angle. Keep in mind I do have cv shafts.
Thanks

You can run your pinion at any angle you can get it to oil. This can be accomplished by overfilling the fluid (like with a Rockcrusher cover).

As far as driveshaft angle, Jess at High Angle says that the max you can run is 22 to 23 degrees. I'm running 22 on mine and it seems to work fine. No vibes, and no carnage. I run it on the street to and from the trails. Jess also said that the angle is more critical on the street (heat production, grease breakdown, and scoring at speed). If it's trail only, you can run a bit more as long as it doesn't bind.