Have a friend thats trying to identify em...

looks like sternpower drives.

Stern Powr, MX1 I believe

Those are Stern Power, Worked on many off them very difficult.

They are the older style. Sternpower updated their transom assembly in later years.

I had MX- 7 on my old Sonic. Do a search, they were discussed a few times. you can still get parts direct as of 2005. Not to many that I see....ever. It was impossible to get props, they now have conversion hubs. I sold my boat with 2 sets of props. Supposedly they could handle quite a bif of power. They required trannies, they were not shiftable.