Re: Wellcraft excel pitch
I would venture to say a 21" pitch prop, diameter is usually irrelevent, and it's size is designed in, in relation to the pitch. but usually, 13 3/4" dia. on that prop. Different versions, of different brands, have different diameters. But, you may need a 14"X19" prop, depending on WOT rpm, weight, or load in the boat.
Just as an example, I had a 79'- 20' SeaRay bowrider (unpainted slick bottom) with a 5.0 (305V8) 228hp Mercruiser with/Thru hull exhaust, and ran a 14"X19" Merc. Aluminum prop, and a light load that did 45-48mph at 4600rpm fully trimmed out.
I figure your boat is close to the weight of mine, but has the bigger 5.7 (prob 350/260hp) motor, so could probably handle a 21" pitch alum. prop. But, a stainless prop, puts more load on your motor, and doesn't flex as much, so if you can spin it the proper rpm it would be faster. If you're looking for an (in the ballpark prop) I'd suggest a 21" Aluminum, get your true WOT rpm with that, and work from there to stay in the proper rpm range.
