Stiletto "X" Dim
 

I had new power built this year and went up almost 30% in HP and only gained 3 miles per hour, the boat originaly had 500HP's with Bravo 1's, Im wondering if my drives are too deep for the increased speed, it seems to hit a wall at 82GPS, doing some research here, Current set up is Dyno 620hp, 1:50 XR's, no Boxes, Std lowers.

Back in the day, I had a 1998 37 OuterLimits hull#24, side by side bravo-1, on boxes. The boat started with T/HP500 and ran 82 with 1.5 gears and a 30 bravo brop.

As I added power I changed to 1.36 gears, kept the 30 props and the speed went up as I expected

I ran:
82mph/500hp
114mph/840hp (once)
103-107mph/750hp
95-100mph/650hp

Wow, nice numbers, did you have shorties or just std lowers with the boxes?

Standard Bravo-1 lower units, before the days of the XR. We obviously did major internal mods to keep them alive, Imco bi-directional internals, Dick Simon Gold Tip prop shafts, after market top cap, drilled out tower and installed stainless steel versions. We gutted the boxes and used the really long Imco torsional shafts.

Now do we need to use my lift to swap drives?
Very nice numbers

anyone else care to share their numbers?

I think someone's dyno's lying, that boat should run 90+

drive heights
 

Stiletto drive heights varied from 1 3/4 to 2 1/4 inch prop shaft centerline above the bottom. Use a digital angle finder, zero on the "V" just before the notch, and set the drives so the propshaft is equal (props removed of course) and see where you are at. 100-200 hp increase usually never needed any adjustment. What does the dyno sheet look like?? How far has the torque fallen off at WOT ? This all makes a difference. Some engine builders only look at the HP number, when its the torque that makes the numbers climb.

I ran it to 88MPH this weekend, seems like the extention boxes make a huge difference on these boats! that will be my next project!

stiletto speed
 

sounds much better, mine's on boxes, 1.50 ratio, spins a standard 30 pitch bravo 5500 rpm, 88-90 mph. boat seems very weight sensative, mine is..