Not sure if this is in the right place but here go's!

Ok let me rephrase my Q? Any help thanks
I have a 29' Scarab running a 21p mirage stock 502 mpi mag turning 5200 60 mph
I have and ran a 23p mirage with the best speed of 65 turning 4800 in prefect conditions!!
But I'm building a new 509 carb'ed motor kinda LIKE a hp500 hoping to make 575-600 hp with all the upgrades we or doing, and I know I'm going to need a prop! So to the big question what would you guys start with? Anyone mess with a set up like this?

I also have a couple of cleaver props that I know nothing about! A 23p and a 25p 14-1/2s I believe or these any good? Or should I just sale them?
Thanks for the help!!

You could try a 25p Mirage +, but I think you'll break it loos and have a hard time getting on plane. I had that problem when I put blowers on my 454 mags. I had run 25p Mirage + very well tried a 27p and all I did was cavitate.
Try a Bravo style 4 blade 24-26p.

I was going to say... If ya can find a mirage 25+ it's a great starting point. Once you try that out and get results you will be able to get a lot of advise. What RPM are you looking to turn?

Looking to turn no more then 5500! I want to keep it low if I can to save on valve train! But not sure yet on what my engine guys gonna turn it to I'm sure 55-6000!

A 25 might be a bit low for ya..... Are you running a brovo? I have always wondered/thought that if ya spin a 3 blade it might help save your drive a bit. One less blade grabbing hard.

I'm running now a mirage 21, solid hub! Bravo 1 dive 1.5 gears turning 5200 but I know that whole set it going out the window, because of the motor! Was wounded how the rev4 work Hurd good things but kinda wanted to stay with a 3 blade BUT, I will say this it has always acted like it needed more bow lift it just seamed like I couldn't get it to air out well! And don't want that problem with the new set up!! About 40% trim it would start losing speed and falling on her face! Make any sense?