Parts aren't really that hard to find, you just have to know what AMC vendors to go to! For the older cars www.ramblerparts.com
is my first stop. If he doesn't have it try www.kennedyamerican.com
or /www.americanpartsdepot.com. www.blaserauto.com
also has a lot, mostly NOS and pricey, but sometimes your only choice. Kanter (www.kanter.com
) has most mechanical parts as well.
In your case you have the needle bearing upper trunnions (all V-8s used needle bearings, sixes used a plain bronze bushing). There are needle bearings in the trunnion (turns for steering) where the steering knuckle pin goes through. Those NEVER wear out! Only the big acorn nuts on the sides that go through the arms. They just ride on coarse 5/8" studs. The nut should move WITH the arm, not turn IN the arm. Easy enough to check, look under the car while someone bounces on the fender. You might want to remove the tire and put a stand under the lower arm so you can see it good. As long as that nut moves with the arm it's good. If you pull the suspension to replace rubber bushings take that joint apart, clean it, put anti-seize on the threads, then reassemble and grease. Should be good for another 100K miles. I always put a small weld tack on the outer edge of that nut (tack to the arm, with the tack where I can get to it with a chisel or grinder). That way it's locked in place and easy to inspect. If the tack is broken it's probably starting to seize and should be looked at. Haven't had one do that though -- not after cleaning and reassembly. Had one wear enough to fall out though! I hadn't taken it apart or inspected it very closely though. It was worn all to hell! Don't think it had been greased in 20 years...