Help with a busted shift shaft bushing

[surveywaters]

To start I have a 1984 Mercury 50EL, the serial # of the motor is 6449981. The shift shaft bushing is omc #23-77631A 2, it is a soft aluminum material, unfortunately, which when oxidized sheared easily. It broke when I was attempting to remove it (I have the proper tool). The top of the bushing has two nocks in it that receive a special tool. The bushing sheared from one nock to the other on one side. Now I can see half of the o-ring at the threads. I heated the case around the bushing and attempted to get a purchase on the remaining material with a punch to no avail. Any tips, advice or ideas would be great. The seal is barely secured and will likely leak horribly.