41 Apache Props
 

So built up 588 Apache motors where 830 HP and 900 lbs torque now 930 hp and 1000 lbs torque have #6 drives, Mercury 4 blades 17 x 27 on now should i go to larger prop and if so what is suggested size.

tks

What was the rpm range of the old engines vs new? Might go up 1”

old ones had old Fireball ignition now MSDS boxes with 6000 rpm limiter but dyno peaked out at around 5500

sorry old ones limited to 5200

More power at a higher rpm, likely to use the same props.

yea i should have been clear at same rpm 5200 90 more HP and 120 lbs more torque
new motors rev to 5500 or so before start to drop a bit

Just to prove to myself , that I cannot afford a boat with #6 drives................ How much is a pair of off the shelf Merc #6 props ???????????

looks like 3-4K labbed 2K more

There's a set of Hering Titanium props in the classifieds 1 of 3 sets in the world known to exist, wonder what the cost..............

How deep are the drives?

17 x 32 4 blade tin reverse rotation

not sure of that #6 but will check

Is This boat near Kansas City? If so, I would love to check it out sometime.

Have you ran it yet with new engines? I would run it first and see how the rpm/speed/ cruise looks compared to the earlier combination. Then you have the data to make a real guess...Which 41' is it? side by side or staggered, full cuddy? Most of them like a bigger diameter prop, some like 5 blades... it really depends on the set up --- trial and error.

What's your drive height?

for reference: I am running a similar setup on #5 drives, old Top Gun side by side, should be pretty close. Drive setups have been -1.0" and 0.0" from bottom spinning out

18" x 30" props - better to get on plane and good cruise around 60mph @ 3600 RPM, 70mph @ 4000 RPM?
18" x 32" props - poor to get on plane excellent cruise around 65mph @ 3600 RPM, 75mph @ 4000 RPM?

If your propshaft centerline is below the bottom, you can run 17" or 17.5" props

It's at LOTO.
Previous owner also had it on LOTO for about 10 years
https://cimg0.ibsrv.net/gimg/www.off...f6688b268f.jpg

Apache Props
 

https://cimg7.ibsrv.net/gimg/www.off...daff495966.jpg
sorry been asleep at the wheel. yes bought it year ago at LOTO was called Bushwacker now Diablo. Smoked a motor with in 5 hours both rebuilt now. 930 HP 1000 Torque it is at LOTO now. trying to figure out drive height. thanks for the responses.

https://cimg4.ibsrv.net/gimg/www.off...edf30d53e0.jpg

Amazing looking boat. Sorry I cant provide any technical information like the other smart people on this forum, but I do love looking at boats.