Replacement for 1980ish Evinrude control box

[ebol5]

This is two questions really... 1) Taking apart the old box (everything in the box which mounts on the inside of the gunwhale, probably can be seen in pic's on the gallery). It is stiff shifting, I have it opened and cleaned except for the shift lever going through the box has the Allen head bolt in the center, removed that but it doesn't want to come apart... I imagine it should come apart but is corroded or some trick? Are these two parts a press fit? If I can get it apart I might consider cleaning it and greasinig to see if it frees up some.

2) If I decide to replace the box, any suggestions? I have checked the internet and it looks like Teleflex has one (CH17000?), there is also a universal... It looks like they all have the connections for cables etc. exposed behind the gunwhale and require cutting a large hole in the gunwhale... any suggestions/experience on what control boxes work best and are easiest change out?