I just googled your gear ratio and it replied 2:1. That helps (over a 2.33 like my 90 Merc) but as steel said, 4500 rpm with a 90 on a 17' tunnel which should run out really well due to flat hull and a 17P isn't much prop. You'd expect your rpms to be on the top side of the recommended rpm band. The 4 blade Stainless will help for a fast hole shot and better gripping, and it probably will have blade cupping which will help prevent your blowing out. I don't know how you could not expect some especially in a turn. Too much turbulence preceding the prop.
The big guns on here always said to get your setup right and then mess with the prop to get your rpms where they need to be. Lowering your engine will contribute to more drag and drop your rpms somewhat and you are already too low according to your numbers. I'm here and you are there, but I think your idea of getting another prop, since it is significantly different might be the first thing you do to cure some of your problems. The problem is determining the correct pitch and an accurate rpm number IS required for that.
HTH,
Mark