31% slip indicates a bad prop or prop breaking loose and not hooking up.

http://pages.suddenlink.net/kmielen/C320Docs/Tach.htm
http://www.amazon.com/Digital-Laser-.../dp/B007KGHD3O

Im sure there are more ways, i just did a quick search.

That method of checking the tach is pretty interesting. Thanks, Sabo, for your legwork and help.

Spoke with Brad at BBlades, and he's hooking me up with a Revolution4 21p after I play with some tuning this weekend. I'll let you know how it all works out.

21p? seems like going the wrong direction in pitch, but hopefully motor runs good and you can get some decent numbers to go off, good luck!
My predictions are if motor running good, you'll hit 60 at max rpm.

21p does seem backwards, but it is a 4 blade vs the current 3 blade. I'd be totally stoked with 60mph. From what I've seen on the internets these open bows tend to lose ~5 mph compared to the cuddly cabin bretheren.

Open bow! didn't realize that, but with the right prop i think you should still run around 65 with 500hp...

just keep in mind, weight makes a big difference, so if you have a full load with 4 people and 3/4 tank fuel your going to run slower

So I put a dial indicator on the prop blades, and with the first blade set to zero the next blade was .03 out and the next was .05 out. Is this significant?

Prop looks decent to me, i don't think this measurement is relative to the issue, but im no prop expert.

My 272 ran 62 stock with a 23 mirage plus at 5050 or so *, would hit 63-64 completely empty no fuel, no passengers empty banging rev limiter (502 mag)

Thanks for the input! Cuddy or open bow?

Yea, I'm getting almost 32% prop slip for some reason. 50mph @ 5k with the same B1 Mirage Plus 23p.