Re: prop diameter
I think you are close with the prop.. see if you can borrow a 21p Quicksiver mirage this is more of a raker type prop, (long ears) so you will need to a least remove your trim tab for a test, because the prop blades will hit the stock one, That is what I used on my old Baja I had to, because the X dimension for my drive was high, I could burn the paint of the leading edges of a stock aluminum using very little trim, the mirage is designed a bit better for holding more trim and running close to the surface, I still use my mirage on my Wellcraft 196 Eclipse with a merc 350 mag and alpha one, because this prop also seems to work well with stern heavy boats also since the longer ears help provide some transom lift, because I certainly do not need any more bow lift, If it is bow lift your looking for then see if you can try a Lazer II, these are designed more for V6 outboards, but can work well with some I/O's also. The Baja was quick due to it hull being what some called a modified v with running pad, but would beat the stuffing out ya in a moderate to heavy chop. I love my Wellcraft for its ride, but its not that much quicker than my old Baja. Overall I don't think your doing bad at 48mph, but a little more tweaking with the prop hopefully you can get 50-52 I think that would be the best you could expect from that package.