What should my pinion angle be with Rough Country 6” lift?

ok now that i know i have a 6" rough county lift what should my front and rear pinion angle be

They need to be whatever doesn't result in driveshaft vibes at ride height and bind at either end of the shock travel. The angles on mine won't be the same as yours. There are too many small differences between the two.
 
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It depends on the type of driveshaft you have (DC or not DC). Post a picture if you don't know for sure.
 
Pinion Angles.jpg
 
Question: does the pinion angle for this layout on top (with C.V. driveshaft) cause negative (bad) castor angle? Assuming yes because I don't know how many other answer could be possible: Is the only way to fix that to cut off the axle mounting hardware for the control arms and spring perches and weld them back on in new locations?

Not usually an issue in the front.
Set the angle to get enough castor for return to center.
Or as far as you can go without vibes.
It is what it is.
Also, I think you would have to cut the knuckles off and remount to do what you're thinking.
 
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Question: does the pinion angle for this layout on top (with C.V. driveshaft) cause negative (bad) castor angle? Assuming yes because I don't know how many other answer could be possible: Is the only way to fix that to cut off the axle mounting hardware for the control arms and spring perches and weld them back on in new locations?
The front pinion angle can cause a bad caster angle but not always enough to need to work like that. The usual and most accepted way of setting the front pinion angle is, as above, to adjust it for as much caster angle as you can get until you get u-joint vibrations from excessive pinion angle, then back off the caster angle just enough to stop the vibrations. Pinion angle always takes precedence over caster angle.
 
Not usually an issue in the front.
Set the angle to get enough castor for return to center.
Or as far as you can go without vibes.
It is what it is.
Also, I think you would have to cut the knuckles off and remount to do what you're thinking.

No need to cut and turn the inner C's. We have a different method. Dial in as much caster as you can get until the vibes start. Dial some back out until it is either acceptable with a nice steering feel at highway speeds, good return to center and no vibes. If you have to dial out so much that the steering suffers, then it is time to explore the option of a hub kit. We focus on good steering and generally wind up with over 6 degrees of caster on 35's.
 
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Here's a fantastic video on adjusting pinion angle. This guy is the professor when it comes to Jeep work. Wish he'd do more videos.

This is for a Rubicon YMMV
 
Here's a fantastic video on adjusting pinion angle. This guy is the professor when it comes to Jeep work. Wish he'd do more videos.

This is for a Rubicon YMMV
Why did the professor not mention a clear differentiation between a double u-joint standard driveshaft and a triple u-joint double cardan?
 
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Why did the professor not mention a clear differentiation between a double u-joint standard driveshaft and a triple u-joint double cardan?

which is why I mentioned it was for a Rubicon. The key points are the angle match between each end.
By 'Professor' I merely mention that he is very thorough with his explanations.
 
which is why I mentioned it was for a Rubicon. The key points are the angle match between each end.
For your 4" suspension lift you should not be running the factory rear driveshaft, you need a double-cardan (aka CV constant velocity) rear driveshaft. For the DC driveshaft your 4" suspension needs the angles should not match between each end. The driveshaft u-joint angles produced by a 4" suspension lift on the SWB TJ are excessive which causes them to vibrate. The correct DC driveshaft angles should look like this....

cv_angle.gif
 
which is why I mentioned it was for a Rubicon.
We almost never don't run a Double Cardan shaft on a Rubicon with 4" of lift. Neither should you.
The key points are the angle match between each end.
By 'Professor' I merely mention that he is very thorough with his explanations.
The only problem with that is what do you do if you still have vibes? Thoroughness would include that he is describing an anomalous install and anyone paying attention should be running a double cardan, if one wanted to be thorough.
 
That previously linked video does an excellent job of explaining the procedure but the answer to the question "what should the pinion angle be?" is conditional to the question "Do you need a double cardan shaft or not?". That answer is conditional to "What are the current joint angles?" All of is explained and demonstrated here:

 
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