I've got three of the old 4 cyl Mercs two are running and one is for parts. They may go that 47 or whatever on a race boat. But a Monark 14'42" bottom aluminum flat bottom built in Monticello, AR in the early 1980's wasn't a race boat if I remember right. I've got a buddy with a 30 2 cyl Merc about 2002-2003 guessing and its slower than my 25 Merc. 14'36 Monark. I'm not arguing I just want to know what kind of boats y'all are running these motors on to try and figure out how to set one up myself!!!