I just want to update this post, This past weekend, I had the pleasure of riding in a grady white sailfish boat which was repowered with f200 i4 4s. The hull was 2001 & was previously powered with hpdi 200's. the boat is located on the Hudson river 1 hour north of nyc. I was impressed on the overall performance with these f200 i4's. we were running at 4100 rpm doing 26.2 knots per gps & burning 14.5 gph, the hudson was flat calm on this test run. The top speed was 43 mph, no canvas & 1/2 tank of fuel, . The hull planed smoothly & performed well. The engines were propped with reliance 17' pitch & wide open rpm was 5700 with 4 bars of trim. The owner was very pleased with the new power compared to the hpdi 200's. Just wanted to post some real world numbers.