You're likely better off with the Performer RPM. I've seen a similar combo; 460 Ford with a marine dual plane (large dual plane with polished runners) - this is on a jet boat also.
Guy at the speed shop talked the owner into a Torker and it went from about 5500 RPM to 5200 at WOT. Definitely picked up low-end but at expense of top speed. It kinda turned it into a high performance tug boat.
Last edited by Rustydawg; 06-14-2009 at 04:44 PM.