So i put an 89 stamped-arm k-frame in my 1990 dynasty ive been putting together lately (mostly because it already had a fast ratio rack and a 1 1/4" swaybar bolted to it).

I had noticed a while back that the cast arms that were on the dynasty were different from the 91-up cast arms im used to. It wasnt until after i dropped the k-frame that i noticed that these cast arms used the smaller sized bushings front and back, like the stamped arms do.

BUT!!! Johnny Spiva says no existing poly bushings for stamped or cast arms fit them, so they are really a useless unicorn and just a curiosity!