Looks like the Kar-Kraft Brighton, Michigan assembly plant that assembled these outstanding cars for the Ford Motor Company with the batteries coming in the trunk as well!
Actually it would fit, the coyote heads are huge and it is just as wide as a boss 9 engine. You might run into hood clearance issues as the boss 9 is taller and the S-550's have a lower hood line than an S-197. Jon Kasse put a Boss 9 in a 08 GT and it fit like a charm. It was so powerful that he couldn't keep tires on it.