Hello bsamx56, Welcome to YachtForums. Since you're asking about the Post 40, I assume you're talking about a wood boat. Take a good look at the fuel tank, which should be under the aft deck, and the ribs at the turn of the bilge. Examine the cabin side for rot below the aft end of the salon window track. In that age wood boat, fastenings should also be suspect. Post built a nice boat in that era. They provide a nice ride and the cedar plank hull rarely had big problems except as noted.
The next generation 42's of fiberglass were good boats too. Early FG models had a wood deck and house, then went to all FG the following year.