RK Steering Issues

I've had my RK steering setup for a couple years now and have never been happy with it. I was reading another thread where someone had moved the drag link on top of the knuckle and had just the tie bar on the bottom but from the looks of it the drag link will be too long to sit on top of the knuckle as I only have a few threads left on each end. I'm curious if theres a way to run v8ZJ steering but have tie rods that are 5/8" since i had to drill the knuckles to install the RK kit?

The only way you will get back to ZJ steering is to drill out the knuckle and use an insert. Google search for "Goferit Jeep insert" and you'll see what I'm talking about.
Otherwise, I think all you can really do is to ream your knuckles for Chevy tie rod ends (the smaller end is bigger than 5/8, at least on the joint I looked at) and run that.
What exactly leaves you unhappy with the RK kit? If it's fixable, it's probably easier to fix it than do something new at this point. And how much lift do you have?
ZJ stuff is out at this point. I don't think there are any tie rods that will fit both your knuckles and the ZJ adjuster sleeve.

What I hate about the Rk kit is how I now have no turning radius, the drag link almost always rubs on the tie bar, and if the front is flexing at all I can't turn at all because the drag link is jammed against the tie bar. I'm lifted 4" with an re 3.5 kit with an extra isolator.

It uses heims right? What size rod end are they?

Yeah it uses heims. Not sure on the size I can't seem to find as much info on it I think they discontinued it.

I'd look around on Ruffstuff Specialities web site and see if you can order just the DOM tubing and adapters, then re-use your heims and run a crossover setup. Your knuckles are already drilled, so hellwithit, just get straight links that won't rub / bind.