Johnson comercial 40 & 55 hp

[SJ40RPT2]

Hi! Have a 1998 SJ40RPTL2. I've been looking through the part lists to find the difference between my 40 hp and a 55 hp.. The only difference I can find is the orifices in the carbs. Is this right? Can I just change the orifices in my carbs, and then got 55 hp out of it? There is two part numbers on the complete carbassy, but both links back to both 40 and 55 hp....??