Geezus!!!
Buick Guys are frugal! Just like a bunch of old men.
Here is the thing... you aren't the first group of people to examine the possibility of using the UBM arms with the stock upper ball joint. But, keep in mind that the ones they sell are very generic... and the stock GM upper BJ is weak. You can't expect it to live long in a high stress (read: racing) situation. The ones that Robert Adams sells are made by UBM, but they have a few revisions, including the larger Chrysler screw in BJ. Saving a buck isn't always the best thing... consider that someone has taken the time to do this right. & Don't expect UBM to send you a set of Robert's arms just because you now know they make them, you have to spent the hours and calculate out your OWN dimensions and submit them... enjoy
Also, UBM isn't going to cheaply design you a bronze upper bushing for the PS. Robert is working on this for me right now, I hope to be the G-pig for the first pair. I emailed him earlier today on the status of my request. And if I have to wait a few days for a reply so the F what?!
Stop acting like children because you can't get what you want, right now! Cut Robert some slack as this ISN'T his day job, he has spent a lot of time putting this set up together, respect that. It saves you the hassle & money. Right, UNGN?
So, if you are really desperate for a complete 12" system you can buy the one that I have in the basement for about 50% more than you would get it from Robert (mine is a Robert Adams system). Or you can go and spend 2 times the money, or more on the upper arms from Global West and build the rest yourself.
I am spent on this topic,