Well guys I am nearly done with my 250 B&M install on my HP500... I need a little prop advise..here is what I had

HP500 w/500hp @ the prop (I massaged the original engine)
Bravo1 outdrive 1.5 :1 ratio
Bravo1 24* labbed
I was running 62mph @ 5100RPM
boat weight around 5000lbs

My blower install should net me around 675-700hp @ prop
I want to run about the same RPM..5100 ish

What prop? I want to stay with a 4 or 5 blade for handling though.

I would put on the 24 and see where your at. You are getting close to needing a xr drive( I just happen to have one) than you can get with Brett at bblades to see what prop you really need(if any).

If you like the way she handles with Bravo 1 props, than try those first.
With the extra 150+HP you are going to need more prop for sure. Likely a stock 26p or labbed 28p B1...

I true 600 hp will bring you into the 26+ range.