Bottom paint can cost a boat as much as 10mph and more and you have a lot of hull and weight in the game there. I am sure more will chime in on this area If it drags at 50mph the drag will be greater at 35...read wetted surface area.

Ok I'll agree bottom paint causes drag. My current issue is I use to run 45 at WOT and 35 MPH around 3600 or so rpm with 24 pitch props and 415hp. I now run basically the same numbers with 26 pitch props and 530hp or so. My bottom is painted the same as it was before the repower. I have more prop slip

Do i have this right your gearing in both cases was 2.0....not 1.65 and your mixing lower's the original lower was?? and the lower your using now...Yes i would imagine your a bit twisted right now. the hull drag (paint has remained the same the only constant...

The ratio remain the same. Was told I needed a 1.65 drive but that was a bust, the boat wouldn't even come out of the water. So I removed the new 1.65 and installed my original 2.0 lower, but changed from 24 to 26 props. Hull has remained the constant.

Trying to put this together in one spot

Before 46mph @ 5050rpm @2.0 gearing gets 19% slip
34.5mph @ 3700rpm @ 2.0 gearing gets 18% slip

After 48mph @ 5050 @2.0 gearing gets 23% slip.......Higher pitch increased speed higher hp and lighter weight aka less drag
35mph @5050 @ 2.0 gearing gets 22% slip........Do those numbers reflect less weight (chain loss)

The hull bottom is constant Hp is up 100...where did the HP come from cam or displacement what was the cam duration????
Its seems you now have the torque to swing a larger wheel no speed gain higher slip and if i read this thread right that came from (speed) less bow weight how much did the chain weigh???

The porpising this is a new thing is it not?

Trying to figure out where to start the head (engine) or the tail (prop/drive)

He is giving up a bit too with the XR upper vs. the standard upper he had before.

Have you tried adding ballast to the stern to get back some of the weight you lost and see how it reacts?

I think at this point its about fundamental's tweaking comes later but that is just a opinion.

Slight difference, trim tabs all up for WOT
Before 5200 at 46mph with 2.0 drive and 24 pitch prop

After 5050 at 46mph with 2.0 drive and 26 pitch prop (up 100hp)

Mid range (34 to 35mph) about the same around 3600rpm before or after

Don't know what the cam is, just that I had to raise my risers 3 inches, use longer runner, and do away with silent choice do to possibility of reversion

Proposing is just that now the trim is real touchy and takes very little to go from none to having some. It's just different and this could be because all the weight I took out of the stern from soaked foam and wood.

Removing the chain actually got me a solid 46mph and started to barely increase above it, but only ran it a little while and there was no big change so gave it up. Guess 110 feet of 1/4 chain and a 30 pound anchor is around 150 pounds max

Did add a bit more water in the fresh water tank to get the boat more level, but don't have it full, maybe 1/3. This helped a bit at cruise speed slightly from less trim tab.

Throw the 24's back on. That motor needs to be turning more RPM at WOT IMO.

The cam duration is fairly important i am sure well maybe sure you have moved the powerband up just how far up is the question. It could very well be you have less torque at 3600 with the new motor and cutting off peak hp at 5050 rpm it sound like your close to reversion...just part of the puzzle. At 35mph how much of the hull is in the water and at wot how much does she lift. Simply stated if you were to cut half of the paint off you hull bottom at 35 mph would the hull ride on gelcoat or paint.

http://www.grumpysperformance.com/Du...Manifold01.jpg