50 Johnson swivel bracket problem

[Panhead Jim]

I disassembled my 50ESL73R to replace the bracket bushings and all of the soft parts, along with updated water pump, new shift rod and housing, et cetera. According to the parts diagrams available, I ordered two swivel bracket bushings, one for the top and one for the bottom. Well, I got in there and it appears that the lower is not removable. I couldn't tell at first what the lower was made out of, so I chucked up a drill to drill out a channel so I could break it and remove it. Quickly discovered it is aluminum and non-removable. So I've got a big problem, since that lower is shot, sloppy. So I started looking on eBay and it seems the later bracket, '79 up, has replaceable lower bushing. Is this true and if I can find one will everything else from my '73 bolt up? Is there another solution? Really need some help here!