Front A-Arm and bushing

[nsx24]

I have a 91' with 69k. i have noticed that i have a clunk noise in the passenger front suspension. So yesterday I tore into it and come to find out the upper a-arm bushing (the one right behind the strut) is bad. I coud move it 1/4". There is a bolt that bolts through the bushing into the other side of the a-arm that I thought I would tighten so I got my manual and noticed that it is supposed to be 49 ft/lbs, I could only get on with a box end so I was able to tighten it a little bit. I put the car back down and the a-arm was now tight so I put the tire on and drove around the block and got back, pulled the tire and it was moving again , so i went to tighten it and now the boltf eels like it is stripped, it just turns and turns, no tighter. Do you think I could strip it? Can I just buy a bushing or does the whole assembly need to be replaced? thanks