Castor advice for 6.5" of lift

[Diesel]

Hey yall, I have a question for you. I just finished my steering conversion using PartsMikes stuff mounted on top of the steering arm on the knuckle, moved my trac-bar up so it is parrallell with the drag-link and now I have death wobble! Well, I have checked everything and nothing is loose but I do know that I have about 1-2* of castor which I know is too little. For some reason, with stock steering and 6.5" of lift, it handled smoother with that little castor, but now that my steering and suspension geometry is right on, I think I need some more. So, what figure should I aim for? Do you think 5* will do it, or should I go up to 6-7*? Just to let you know, I have RE 4.5" ZJ springs, stock isolator, 16" fixed lower arms, RE adjustable uppers and RE drop brackets. The weird part is that in order to give myself more castor (shorten the upper arms since the lowers are fixed and I don't want to use those shim things) I have to cut some of the threaded tubing on my RE arms. Right now they are adjusted all the way in. It seems weird that anyone would need the ammound of legnth they potentiall provide.
So, to make a long story short, what castor are you 6.5" guys running?
Thanks,
Bryan

 

[MaXJohnson]

One of the components of death wobble is a coupling of the steering motions of the left and right wheels. In most respects, a straight tie-rod from one steering arm to the other is a good thing, but in the world of death wobble, the added rigidity between the left and right wheels can contribute to the problem. The inverted "Y" is slightly less rigid in this respect.

IMO, if you can get away with it, 5° or 6° would be good for your castor setting. Problem is, you'll have to consider pinion angle too.