Not sure on a 4 blade but a switch to a 17 should be right at +400 RPM - my 200 won't quite swing a 19 3 blade

raising the motor probably would help since you have a better prop - 1 1/2 to 2" for the Cav plate above the hull bottom with a prop like that - shouldn't need any prop shop adjustments, leave the cup in it and raise it