502 strocked to 509 new pistons, rods, heads, cam, etc, etc. Retuned, estimated hp ~600. Running dry headers (water reversion is what killed the stockish 502). Drive is stock with the exception of add-on external steering. I have a drive shower and I also swapped the water intake from the drive to the transom (lots of shallow silty areas in FL which were a pain with the low water pick-up). The drive pick up now just pressure feeds a hose and I installed a dump right over the top of the drive, works like a champ. No other changes to the hull but I have always seen ~1-2 mph faster than others claimed. I could always just walk away from my buddy with a 25OL 496HO even when he was alone and I had a boat full. The most challenging thing with the engine upgrades dealt with the valve covers. The new heads had higher lift rockers and I had to install the taller valve covers. This lead to PITA issues with stock merc mounting locations. All things considered it runs great, the only issue I have is slight loading up if I am at dead idle for along time. Everything clears it throat after getting back on the gas and I change the plugs farily frequently.

NICE!! Its good to see other 25OL out there beefed up. If your on the limiter now you could definately turn a 28 or maybe even a labbed 30. As you test more props start another thread documenting your before and after results.