After finally installing my GPS chartplotter and Air /Fuel ratio gauge in the dash, it was time to get the tune checked. I have about 8 hours run time on the 502 motor so I felt it was time to let it rip! I had a fat idle that I was able to pretty easily correct using the mighty demon 850 and my original choice of jetting just happened to be about perfect! Temp was 90* yesterday when I went out........I used the same jets as a similar 600HP dyno test I found and it is very good. Idle is around 13-14.0 and 3,500rpm cruise is right at 13.5.... it goes richer from there and 4,000rpm is 12.5 and max rpm was 4,900rpm at 11.5-12.0 with a 26P B1 prop at 69MPH...... this was in flat water on a river so maybe I might get a little more rpm in a light chop? I am considering maybe dropping the secondary jets down 1 size but I think having the tune a little fat is safe...... I will be cruising 90% of the time at 3,500rpm so I think I am good! I was expecting to get a little more rpm out of this combo up around 5,200-5,300rpm but I am overall happy with how it performs. I know I could use a mirage prop to get more top end but I really like having a 3,500rpm cruise at 50mph so I am ok with sacrificing a little on the top end...... this is my first performance boat so I want to make sure I am in the ball park with my results!!

Sounds great, tbf. A little light chop and some slightly cooler air will easily have you over the 70 mark. I'll have to dig around for your build specs - they all start to run together after awhile, but I think I recall that you were running one of Bob's cams in your combo. Hope mine runs that well. Did you dyno your engine?

Also, you mentioned that this is your first performance boat. Sometimes a little extra playing with the tabs and trim can wring that last few MPH out of the top end.

Yes, Bob's cam is perfect! I have a little bit of a choppy snarl at idle and plenty of torque everywhere in the power band...... And no reversion with silent choice! Hah! I am using aluminum 496 manifolds and the 10" risers with great success. I was curious if the bow should come up a little bit more as it seems the boat rides very flat? I have aluminum heads,intake, exhaust and that saves about 300lbs right off the back of the boat and I wonder if this might be affecting the normal ride angle? The boat does sit very high in the back and gets on plane quick even with no tabs......Even with the outdrive trimmed full out the nose of the boat just does not come up out of the water that much? It feels like it should and I don't know if the rear step is out of the water and doing its job?? Otherwise the boat is pretty much awesome!

The 4 blade props typically provide more stern lift over bow lift. You may want to try running something like a 25 Mirage Plus 3 blade - these should provide more bow lift. You might find that your midrange doesn't suffer all that much.

Thanks, I heard that they sometimes blowout a bit while getting on plane and the slip is higher at lower speeds..... I wonder if a hydro motive 4-blade prop would give me a bit of bow lifting?

Bravo 1 26p is the right prop. I had a very similar setup and they do not like Hydromotive or 3-blade props

I checked my slip numbers and it is very good at 15%.... I think as Second Chance said it is the right prop and I agree and will stay with it... but it still seems that the boat is bow heavy? maybe not bow heavy but it seems like the hull will not release fully from the water and really take off? Stock 502's would push this hull to 70MPH with 415HP and I am at least 100HP stronger than that and only getting 69? The boat always feels very well planted in the water and very stable...... maybe too stable? I have 2 drive trim switches with one being for the trailer and even with the normal trim switch out fully the bow does not bounce on top of the waves like I would think it should?

TBF, did you ever figure out what was limiting your top speed? I finally pushed mine hard Sunday and had disappointing results. Only saw a little over 60 and RPM's weren't where they should be. Going to check the obvious things like throttle position opening and timing. Might start a separate thread, but need to check some things first.

Have a qft 850 I'm putting together for a 502 now . Came with 85 squared ,f+r power valves .,real close to what the old 460 cyclone ran I believe , curious with what you went with on yours .and is it closed cooliing