Apart from the Suzuki Ali Prop not biting quite so nicely, I have found it to be pretty much the same as the equiv 21" stainless prop I have on there now, in terms of both speed and engine revs. As it stands, on a good day, with 2 people, the thing will reach 6000revs at 43knots, a bad day with 9 people on, it'll do maybe 5500revs at 34knots, both figures at WOT. I am certainly not going to be trying a 23" prop, but it's fair to say that a 19" would get the revs easily upto the 6200 mark.... but this is quite high for a 4-stroke marinised car engine though isn't it? Even 6000revs is high.... the boat cruises nicely around 22-26knots at 4200revs.
I wouldn't mind the 150 suzuki now though - that thing I'm sure would get at least a few extra knots out of the destroyer hull.
Many years ago, I did my L1 and 2 on a Destroyer 7m with Johnson 200hp Venom on the back - talk about fast, soft and dry.... it was then that it was Destoyer that was chosen