Using sphericals in the rear is the only way to get all of the slop out, and have the suspension go through the full range of motion without binding. Period. The front LCA's don't have to be spherical. I have delrin in there, and they work fine. But the TC rod bushing should be. I am one of the few people that have machined all of my own inserts for the car. It can be done if you have a decent quality lathe. But it will require many hours of labor. I recommend that you make one each of the two or three different size inserts that you need on the lathe, and then have a machine shop duplicate the pieces to your specs. You will still have to install everything but it should save you some time and money to do it this way.
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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56