1998 35' fountain top speeds
 

I'm trying to figure out where my top speed should be. Just pick it up. I'm running 28p 4blades 502 500hp carb motor but turning only 4800 rpms. Still haven't rung the nuts out of this ***** yet because I have encountered only 3-5' seas every time I have gone out. I know the boat is supposed to run 80-84 mph but I have only seen 78 at the moment. Not sure if I'm do to rebuild the heads yet. I'm tying to figure out if the hrs listed at are accurate. Can anyone tell me there hrs and there top speed with this set up so I can try to figure our where I'm at. Thanks in advance p.s. Drives turning in

Drew, I have a 98 35 Lightning with whipple charged hp 500s turning 29 pitch props, the boat runs 93 mph at 5100 rpms. It took me a while to get enough of the boat out of the water at higher speeds, btw I also have stand off boxes. If you call Fountain/Baha, they will send you a build sheet and performance sheet, tells you exactly what the boat does, but your numbers are simiiar to what my build sheet shows, my boat started out with HP500 carb motors, and shows 84 mph.

Do not know if this will help you out but I have a 93 Lightning with hp 500's that I have seen run 81mph on gps at 5100 rpm's. You're rpm's might be the issue. Not an expert, just going by what I have experienced with my own boat. The 93 is also a straight bottom.

28 Bravo four blades, sorry I left that out.

I don't see a 98 35 with 500's running 82-84 unless you strip everything out of it...I would try a pair of 26's as you need to get the RPM's over 5000, but I'm thinking that would be about 78-80 GPS

Are you running factory HP 500's, 78 -80 may be all in with the boat full of fuel and extra weight. ,Also carb. jetting, timing ,drive trim, etc. can help.

im running twin 496 h.o. motors in mine and im getting 76.5 on GPS balls to the wall

I hit 77 on gps with half tanks, 4 people and blown motors? Port motor half the had 80% leak down. And on starboard side best was 40% . Now I don't know where the hp would be under these conditions , but my new motors will be around 580hp on desktop Dyno . Also these boats I thought were spec. To run 84,85 mph in there test runs. Sure with little fuel and a driver on a flat day. But would it be safe to say that with that kind of leak down I'm only around 300-350 hp?

No way your running 77 with 350 a side... Your right on par with a heathy 500hp boat .. maybe a few tics off, the twin step 35 (2000-03) were seeing those kind of numbers w500's

No , you have way more than 350 HP. each engine if running 77 on gps w/ 4 people,,more like 425-450 hp each, an HP. 500 is 485hp,,, FIVEPTOHH , is running 496'S, and you are same as him on speed, what is compression on each now compared to leak down., and what brand props are you running, reworking the heads will help, and maybe the props need worked also.