I've got an 89 celebrity 187br with the merc 4.3. 14.5"x19pitch prop, all trimmed out she does 37mph at 4400rpm (gps).I don't know how other celebrity owners are hitting 50mph with the same setup.
I'm not sure but i have an 89 215 21' bowrider im sure it has a 19 pitch prop it has a 355 chevy (5.7L bored .30 oversize) with the stock alpha one behind it motors pretty well stock other than the machine work and new parts for the rebuild I've only had it up to 35 mph (very small lake) anyone know what this boat would approximately do with say a 400 horse motor??? not meaning to hijack your thread