An '82 should be a Seacraft Industries hull (HIN starting with "SIC"). My '83 has scuppers that drain out the transom, and a 25" transom that will allow a little more motor. Mine is also 8" longer than the Potter SF 20 at 20'-4", but I don't know when Seacraft Industries retooled the mold. If it's the longer version, it will have the small spray strake near the forward ends of the center panels like the Potter 18s and 23s.
Check for soft spots in the deck or gunwale cap and flex in the transom. I have a 200 on mine, but I think the best power for this hull is probably a 150.
Dave