That's just an oem swinger that's 88-90, the later model chain sliders bolted on from the side. Just order a new oem slider.
87 swingers
**** so they updated the slider mount to the side.
weld a 1/4 inch thick plate to the top of the arm then cut the slider ot fit. did my buddies that way and its still holding up, no cracks.
Thanks Shawn, cworobec.
I think that idea is going to be the plan, thanks
forgot to add, i welded a threaded round piece to the side where the 88-90 slider mounts. no more need for the threw bolt.