Well make sure you buy parts from some one else other than them.
They are 2 different parts, the KJ arm has the ball joint pressed into it and the ball joint shaft is bolted into a bracket on the diff.
The Wj arm has the ball joint bolted to the top of the diff and its shaft locates into the arm.
There is a guy on the lost forum that fitted an aftermarket WJ iron rock upper control arm in his KJ and made his own diff bracket to locate the bush at the end of the arm. His set up eliminates the ball joint and adds the ability to adjust the pinion angle. The only similarity between the 2 parts is the distance between the mounting point.
Sounds like the parts guy nows a friend that knows a friend that heard of someone that new someone who's cousin once heard from a friend who reckoned that someone they new heard from someone else that knows something about which they really now nothing reckoned that the 2 parts are the same.
Which is why you have to dig through so much false information to find the facts.
Oh and perhaps the actual bushes that fit the arms are the same but I shouldn't really suggest that cause I don't know for sure!!!!!!
Last edited by jaffazoom; 17-09-2018 at 04:59 PM.