Thanks for all of the input. I read a thread in GD that discussed the octane change to 87. I also read about the reliability of 600's in the same thread (except for the XR drives if you're not careful). If I end up with a flame, it will have 600's. As for modifying 525's, I wouldn't even consider it......I'm in to reliability. I can't work on these things and unfortunately no one in my area can either.

I definitely like what I'm hearing about speeds. I would be extremely happy with a solid 95 MPH.

The drives should hold up OK. The biggest problem is in big water were the boat & drive leaves the water. Re-entry is what causes them the strain. I allways play with the trottle if I leave the water to take the load off the drive. The 600 should work great in that boat.

Food for thought:
I have found my 30 Bravo 1's get 12% slip on the 35.
RPMXGear XPitchXFactor=SpeedXSlip=Speed
5300x1.50x30x0.0009470=100.38x0.880x88.34

The 525's in Gary's boat run 32 pitch 91 at 5300 if I remember correctly. 15%
RPMXGear PitchXFactor=SpeedXSlip=Speed
5300x1.50x32x0.0009470=107.07x0.850=91.01

If the boat runs between 95-97 you would need 34's
The 34's have a lot of slip. The most efficent Bravo1's are the 28's out of the box.

I would get the drives with 1:36 gears & 30 Bravo 1's
RPMXGear XPitchXFactor=SpeedXSlip=Speed
5300x1.36x30x0.0009470=110.72x0.880=97.43 12%

Linster, You are quite the scientist!

Linster,

I hate to sound like an idiot, but you just lost me. 34's have a lot of slip? Does that mean out of the hole or while running? Are you suggesting something other than Bravo props? I just assumed that mercury would set the boat up with the best possible configuration out of the gate.

Linnie is just saying that after 30's the Bravo prop's efficiency falls off quickly. You would more than likely see more slip everywhere with 34's.

Linnie, are your 30s and Garys 32s labbed or stock?

I'm hoping to be able to spin my 30s to about 5500 at our high elevation if I'm lucky. I'll be cam'd for the 5700rpm range so that will be a good starting point for prop work here.
Who knows where I'll be at sea level :rolleyes:

Thx,
Dave

Hey Dave,

My 32's are labbed. I tested the boat this past Sept. with Tres Martin where slightly less trim (5.5 vs 6.5) and slightly more tab (5vs4.5) achieved the best top end numbers. I have always had the tendency to over trim and under tab.

Decided to add the 380 K-planes (longer than the stock 280's) and try a 31 labbed Hydro five blade. The longer K-planes should extend the boat enough to deduce tab influence and grab another couple MPH?

In the end, the 35 Nordic is one of the fastest 35' Vee Hulls you'll find in production, the 600's will make it even faster.

NG

Is anyone interested in an 05 Heat w/525 xr/its, dana tabs, electric seats, closed bow and trailer. Great cond. What do you guys think it is worth. All this talk about the 35 is givin me a chubby.

We will gladly take it on trade for a new or used 35..

Unlimited Marine.com

The 34's are more slip through the entire RPM range. When you pitch a prop, you are raising the blade up so it actually pushes less water at a more extreme angle. With more pitch you should actually need more diameter. In cats the effect is less than a V bottom, because they glide more, less wetted bottom.

Second, Mercury only sells engines & drives, they leave it up to the manufacturer or the owner to set up the prop & gear ratio.

Hope that explains more.

Dave, my comaparisions are with the labbed 30's Gary put on the boat. They were 2 mph faster than the stock 30's now. I just got them back from being labbed

Spent way too much time on this boat crap. 26 years now with power boats & engines.

Hope all is going well