Volvo Penta prop selection
 

Recently built a 500hp 509. The original motor was a 300hp volvo penta vortec 7.4l. The original F6 props are too small. With an extra 200hp should I get the F7 props or possibly the F8 props?
Currently @ 5200rpms with the F6's w/ 1.95 gearing. GPS is 55.4 @ 4300' elevation but the jetting isn't dialed in yet.

It all depends on the rpm you desire at WOT. And that depends on a dyno sheet.
5200 sounds fine for the 509 at 500HP.

Brett