I don't think I meant to say the 226 is a dog. But I have worked on modern cars with turbos and superchargers and so my reference comes from them. In many cases, initial compression is reduced because the boost from the supercharger (or turbo) could destroy the pistons/valves.
I don't know the engineering behind the 54-55 226 "blown" motor so I was assuming it would be a dog from a lower compression and timing aspect, as compared to a "normally aspirated" engine. But, apparently I am incorrect.
The bottom line is even the supercharged 226 was not keeping up with the Jones' in 1954-55. So, most of us would not purchase a 54 for their performance. As admirers of KF, and given that only 4000 or so Manhattans were made, we would collect and restore this one for the styling, place in history and camaraderie.
Hope it can be purchased, maintained and restored.