Removing twin chevy's -Outdrive ??'s

[desertmariner]

Hi I'm new to this so here goes.. I have acquired a 1986 2850 bayliner with twin chevy 5 liter engins with 4 barrell carbs. One is sized up and the other has poor compression. Anyway I've decided to yank the engins and have them rebuilt. We plan on doing a bottom job while it's hauled. I'm limited to the time I can have the boat at the yard.(Its a week-end project). What all should I do while It's out of the water with regards to the outdrives. I'm afraid I don't know what kind of drives they are by the way. Any help would be appreciated. The boat is not trailered and lives in brakish water full time.