Pitch question
 

What’s up guys. I have a 28 Pantera 598/800ish HP. Currently turning a 1.5 with a worked 26P Hydro quad x running about 80@5600. I know the heads make max power at 6k. Should I drop pitch to get to those rpms? Change prop? What would be the best way to get max speed without messing up my very comfortable 50mph cruise? The builder said he ran a best of 84 in the boat with a worked 28P bravo 1 at roughly the same rpm.

any advise would be appreciated. Thanks

Your propslip -13% is quite a bit lower than most other 28 Pantera's. I am surprised you are only turning a 26" to 5600 rpms with 800hp. I had a 28 Pantera and turned a tweaked 26 Bravo to 5250rpms @ 67 mph with about 560hp. My prop slip was high at about 20%.

Your heads may be good to 6000rpms, but that does not mean the rest of the engine was designed to run that much rpm. Only a dyno sheet will tell what the best rpm is for torque and hp. Personally, I think you should be running something closer to a labbed 30" Bravo prop.

Engine is built to run 6000. I’ve spoken with the engine builder many times. He always says “Let her eat”.

Post a dyno sheet.

https://cimg2.ibsrv.net/gimg/www.off...369366bec3.jpg
Dyno sheet

The engine itself has really good parts in it. Mahle Pistons, Oliver Rods, Callies Crank, Merlin Block with billet main caps, Brodix CNC Heads, matching intake, Johnson Racing Lifters, Isky Tool Room Springs.

From looking at that sheet you'll be ok spinning it anywhere from 5600-6k. The HP curve is really flat there. The torque curve is downright impressive. It's just gonna be a matter of getting the correct prop on it.

if you have the valve springs let her sing.... we run a similar engine combo with a 1.50 xr and 4 blade bravo 26p in a early 90s 25 active thunder hull, we turned it to 6800 a few weeks ago the boat is a great combo and really rocks we have a valve train good for 7500

Thanks. I built it a few years ago. Although it makes power to 6K the boat always liked to be propped in the 5500 range. We tried propping to get the RPMs up and the boat went slower so basically you give it what it wants.

With the right prop the boat runs a consistent 84-86mph. Previous owner ran over something and ruined the labbed 28" Bravo 1 prop that was on there and wasn't able to find the right prop since. We tried BBlades, Hydromotive etc and the best prop was a labbed 28" Bravo 1. The only issue is that we don't know exactly how that prop was labbed or who labbed it as it was a hand-me-down. I suspect that it had some diameter cut out of it because we did run an old labbed 28' that a buddy of our had and it didn't like it but for whatever reason, the 28" that we ran for years was the fastest prop.

The boat has an SCX on it and it robs at least 3-5mph so keep that in mind.