Well for this is worth, I had a '86 220 Sport, least that's what the "no title state Georgia B.S." bill of sale told me. The previous had put a RamJet 350 automotive crate motor in it, Gen I Alpha with nose cone turning a no-name 22P SS. That engine was rated at 350hp, 400 lb-ft. and turn to 5200. With just me in the boat, 225 lbs. the boat would see 64-65 indicated. The gages were new but still just gages. It was a dog on the bottom end but look at the dyno sheet for the RamJet and you'll understand. I know this is nearly 100 more horses, but even with liberal prop slip estimate you're too slow.

Damn I loved the ride of that boat. I felt fearless at the wheel. Wife hated it.