I think inertia had the best idea for the stock UCA's if you wanted to use them. Buy or make a ball joint plate to switch the ball joint over to a bolt in style, no more wearing out threaded ball joint mounts.
You could cut the end off the factory UCA, through the flat section. If you did this at an angle, it would add caster. Then butt-well the ball joint mounting plate to the factory UCA. Either section back, or overlap the shoulder on the factory UCA with a piece of flat stock, wrapping it and welding it all the way around the plate if possible to create a shoulder on it as well. You could then gusset the ball joint mounting plate to the UCA across the bottom with a flat plate, or get really fancy and gusset it across the top, shoulder to shoulder, with a section in the middle coming down to tie into the ball joint plate.
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All said and done I'd just buy a set of SPC adjustable UCA's. Much less work and double adjustable. Probably not even more expensive if you figured your time at the shop rate for someone that could do this kind of work.
