If you have a tachometer then you can set up your motor for its’s best performance. Doing anything without a tach is just a guess. You need to know if your motor is running at it’s best rpm range, to low is not good for it and over reving will create a problem. The prop your are running now may not be the correct prop, but you won’t know unless you have a tach.
Thanks guys, and thanks for the link. My tach puts me well in range right now, but I was just kinda curious what I could do with a prop since I had another couple of inches of space. I know just because I have the space doesn’t mean I have to get a different prop, but I was more curious about the possibility of improving speed somehow. Thanks again, and I’ll go check that link when I get a few minutes.