I think the previous owner could have added more crap to the rear of the boat if he really wanted.
I've seen four or five SeaCrafts that were changed from twins to a single 30" shaft engine, including my brother from twin 140 loopers to a single 250 Merc and in every case the owner was very, very happy with the performance. Some were hung on the original transom built up to 30" and Moose's case with the manual jack plate. For a diver or someone who needs to use a ladder to climb in and out of the boat that's a real nice set up!