Horse power

[Waterman]

just looked at a GREAT 1989 v20 yesterday boat was in excellent shape and even ran great but it had a 140 hp johnson on it and was very slow could barely get it to plane off at full speed at 5500rpms at a cruise 4000rpms boat only got to about 18mph I ve heard you guys say a 150hp was minium but does 10hp make that much of a difference? and what hp should i be lookin for on the next one?......... really hated to let that one go