24 x 7 prop talk / help!?
 

Need some help with props......
Boat is a '91 Sunsation Rocket.... Similar to the rest of the 24' x 7' hulls (Pantera, P&D, Banana Boat, Superboat, etc.)
BBC with Bravo1 1.5 ratio

Previous motor was a 454/330hp with Edelbrock aluminum 110cc chamber / 290cc intake / 118cc exhaust marine heads, Edelbrock 7562 manifold and Crane H-296-2 cam.... allegedly was 500hp range but who knows.....
With a stock B1 prop 26pitch:
3500RPM - 40mph
5400RPM WOT - 74mph and chine walking like a *****...
_________________________
With a Mercury Revolution 4 prop 25pitch:
3500RPM - 45mph
5400RPM - 74mph (same lol)
Rev4 prop gave amazing plane time and excellent mid-range speed and same top speed as B1 but far more stable.


Ended up with a new motor...
489 stroker with Merlin I-043c heads 119cc chamber /320 intake / 137cc exhaust, same Edelbrock manifold, and custom grind cam (attached cam card in pics)
Dyno'd at 530hp / 579tq (dyno and graph in pics also)

So with that said, Im getting pretty much the same speeds with the Rev4 prop but its amazingly quicker getting up to those speeds....
What Im wonder is if I can step up to a bigger prop?? Maybe a 28pitch Bravo1 or if there is a bigger Rev4 prop out yet?
My thinking is maybe this newer motor makes more power down low, especially the torque as its a stroker..... It revs up amazingly fast and has almost no lag.... where as the 454/330hp worked motor made its power higher up possibly and had some lag getting up to that speed.... so the new motor is max'd out at that 5400/5500 RPM range considering the dyno graph.... So much more torque and HP is closer to 5000RPM or so.

I love that Rev4 prop, and pretty sure they came out with a Rev4 XP or something... and has a 26 and 26.5 pitch options... but its under the outboards section?? Isnt this still the same prop shaft that it would work??


Thoughts?? Suggestions!!? Thanks in advance.






http://drive.google.com/uc?export=vi...mYtMVhnaE55SDQ

http://drive.google.com/uc?export=vi...lU5QkR2bWRxZVU

http://drive.google.com/uc?export=vi...zRpcl9Yak8yN28

few things to think about...

1. what do you have for steering? it those speeds in that hull you need full hydraulic
2. have you laid a straight edge on the last few feet of the bottom?
3. I believe the rev 4 only goes to 25
4. the Rev 4 has more bow lift than the bravo 1, If you dont get enough bow lift on that hull it handles like crap. (I tried an old school cleaver, lifted the stern not the bow, and the boat was down right scarey)
5. How deep is your drive? A deep drive on a narrow hull single can get a lot of side torque increasing as you go up in prop size.

Thanks for reply.... Answered the questions above...

Anyone??

Pics you attached in 1st post not working

Dammit.... thanks for heads up.... forgot to make them public!!

Not to sound like jerk but you really have no reason to be running 75+ in a 24/7 without full hydraulic steering.

If your pulling 5400 rpm easily you can probably swing a little bigger wheel.

Try a 25P Mirage Plus

if you right click and open in new window they will show up.. Dyno sheets and cam card

Lol - not at all.... I just figured seeing how its running soo smooth at 74, a few MPH on a bigger Rev4 if available shouldnt be terrible.
Ill keep an eye out for a hydraulic steering kit I can afford though