a 3 blade may not give you enough bow lift.... Others on here know a LOT about this... someone else will chime in with more tech info.

I have never been able to get a 3 blade to work on my 27 ft baja with a blower (slipped like there was no tomorrow and broke loose at high speed). As far as propping taller,as you prop taller your rpm's will drop,as your rpm's drop your motor will make less boost. As it makes less boost it will rpm's less,it's a viscious cycle. A labbed 30 will rpm close to what a std 28 will but if your only turning 4900 then it's too tall and like others said you will have to lab your 28 or go even lower. Try some props before buying any,this will also give you more info to help decide what will work best-ex: it turns 4900 w/28,turns 4500 with 30 then you know a tweaked 26 is the way to go,Smitty