You honed a 502 to a 509?

I stayed naturally aspirated. My engine builder (saris racing) kept me in the loop from the beginning and we talked about realistic goals for my budget and future maintenance expectations. The motor was brand new, top to bottom, balanced and blue printed lower bearings etc. Dart pro 1 aluminum heads were installed, along with a custom ground cam. I don’t have specs on it in hand but in a nut shell it is slightly more aggressive than a stock 525efi. I also eliminated silent choice to be on the safe side for future reversion. The engine is also a 516 CI. When I bought the boat, a top end had been done due to a valve failure and was told it was still a stock 502, which was not true, although the boat ran great for the first 5 years I had it. When saris pulled the engine and began tear down, they could see my silent choice was reverting water, and that there was still damage in the 2 cylinder walls where the valve debris had fallen from the previous rebuild before my ownership. I decided to bore again, taking care of any previous damage. After put all together, the engine was then tuned on the dyno and pulled 585 hp at 5400rpm and 640 ft/lb at 4000rpm. The big limiting factor is the stock 500efi intake after 5400rpm. That first summer, the best I saw was 80.1mph. The following summer I did the Hardin marine throttle body upgrade and ported the plenum to accommodate the larger mono blade flapper. Just by doing this I gained 2mph! It gave me 150-200rpm at WOT. That’s why I say 600hp. At this point I’m done with mods, there is nothing more I can really do to gain anymore without sacrificing reliability. I also have an XR drive, and like stated, is the weak link, I like the drivability of this setup without worrying about a supercharger or drive issues. If you want to be more into the 700hp range, supercharger will be the way to go.