Ok, sorry that this is a dumb question and normally, being my boat, I like to think I would know the answer but... Situation: I did a winter draining for my buddy on his 96 Cobalt 454 Volvo Penta Drive the other day and only found two plugs (one ea. side) in the normal position I would expect to find them on the lower jackets of a mercruiser (no riser plugs visible). Did I miss any? Sure would hate to have his block crack and my seemingly good deed go wrong. 