I had the blocks on my America for a while (took them off after meeting my new girlfriend who loves to ride; the back tire would drag), anyway the angle was definitely not good for the bike; it would bottom out and rode like a hardtail, plus it started wearing the bushings out. Had I kept them on, I would have had spacers made to get them at the proper angle. I may still do that depending on the situation with my new girl haha.
Lee