A 23 mirage plus is a good starting point as griff said. Call BBlades and talk with them about correct pitch and their test program. Good people there

Thanks man.

I boat with a friend who has a 496HO H2X that has minor work done -- we don't know what that means, it has a "custom tune" from the previous owner and a Bblades labbed prop, our boats are damn near dead even with two people and similar fuels loads. We would have to run for a LONG time before either of us pull any distance on the other and mine is just a hair quicker. I've seen best of 71.5 verified with GPS, though I am sure it's run faster in choppy conditions, a little chop wakes up my boat. With two people on board an 3/4 fuel I'm just over 70mph on GPS. I can't speak for the 502, but I'd have to think it's pretty damn close. I say 70 or a little over is VERY realistic, then again, I've seen identical boats be 3mph different...

I have no idea what it would run "stock" since he don't even know what "minor work" means…but I'd guess upper 60's.

Well we used a gps and a app off the phone and I was wrong on my speed. With a half a tank and 2 people I'm only getting 52. I wish I knew more about the boats but this is my first and I'm trying to read everything I can and get on these forums. It's frustrating having a boat that sounds so mean but can't even break 55. I'd like a tune but not sure where to send it or even how to. Works kept me so busy I haven't had a chance to figure all that out. What props do you have on yours?

Bringing this one back from the dead. Did you change props or get the boat in the 60 mph range?

Plug the numbers in yourself. This is my favorite calculator its usually right there. Figure 15% prop slip 10% is doing great.
Propeller Calculator / Prop Calculator