Thank you for replying to me.
You are right, I should buy a entirely new “counter rotating lower unit”.
However that's extremely expensive.

My plan is to change selected components of the lower unit of one of the two 225HP 2.4L engines that I own which are both right hand.
I understand there is not a “conversion kit”.
As alternative, I am looking for the parts list of the left hand lower unit so that I can compare it with the normal rotating lower unit list and to extract what components I should buy to make the conversion. Can you help me?