The 722.3 ( lager capacity 4 speed ) and 722.5 ( larger capacity 5 speed ) are very similar / share some parts with your .4 so I'd have a look there too.

Later trans supposedly did not have a rear pump so swapping a later gov cover might be the most direct route if you have damage. I had thought rear pumps went away prior to 91. ( like after 86 )

Generally governors have springs / weights tuned to the car so you might have some shuffling there.