What motor you got and what are your plans with it?
Most companies made one motor,put diffrent carbs on them and rated them for diffrent hp. 25-35hp johnson evinrude 40-50hp johnson evinrude,9.9-25hp,60-70hpjohnson evinrude,40-50hp yamaha, 60-70hp yamaha just a few examples. Same motors diffrent carbs. Some have a little diffrent exhaust tuners or diffrent timing.
Easiest and cheapest way to make power is raising compresion by shaving the head. Letting it breath a little better by cutting holes in the breather box can help out a little to. Raise compresion,reeds, rejet carbs, and new exhaust tuner are the way to start building power. Then if your real power hungry break out the dremel for some port work. Before you need to think about the dremel you need to hit the books and do a couple months worth of research to make sure you don't turn a good block into a good boat anchor. :mrgreen: Mod at your own risk, hp is addicting :twisted: