I would like to put an OMC cobra 3.0L upper and lower unit on my 4.3L OMC cobra boat(lower unit is cracked upper unknown no oil). Can this be done mechanically) the manual seems to indicate that the upper units are identical. What will need to be done to make this operational as far as prop or linkages are concerned? 4.3 liter 1986 VIP 19' runabout