Prop for top speed

The prop's diameter is boat specific.  Not too big so that the blades pass too close to the hull, and not too small so that the prop sacrifices efficiency.  The pitch should allow the engine to just achieve the engine manufacturer recommended maximum operating RPM at wide-open-throttle (WOT).  External impacts on WOT engine RPMs are things like altitude, people / weight in boat, etc.  The cup will also impact propeller performance.  The cup is the "bend" on the prop's trailing edge.  The idea behind the cup is to change the effective pitch by adding camber to the prop blade shape.  So, a prop with less pitch and a bigger cup may allow the engine to spin up faster at slow speeds without sacrificing too much speed at WOT.  Keep in mind that not all "cups" are created equal.  Cups will vary in effective pitch.  One rule-of-thumb for cups is: "When using a cupped propeller, the design pitch value should be reduced by 1-2 inches compared to the non- cupped propeller."

So...not an easy answer.  Also, a repaired prop often (not always) does not perform as well as an original (non-repaired) prop.  Give 'em both a try and see how the boat performs.

CCF member TRBenj often frequents the site and has a lot of good info on props.  He can likely give you more useful information.

JQ

JQ gave you the only answer you really need, due to all kinds of variables ...........try both props on the boat.

From your description and no picture, .your other prop is unknown to anybody

It could be a newer design Acme 422 as a guess, but a prop swap will tell you everything you're trying to find out

Still the same answer...........try both

11 out of 10 people would say to put the 422 on for a try/comparison

Umm.............go read what he said again

4000 rpm they each went 38

4800 rpm they each went 41