29' w/ 600 HP
 

Could a single step break the 80 mark with this combo?

I think there were 10-12 of them built at the factory 85-87 mph

I'm just kicking some ideas around, nothing serious.

The 575SCi 29 Fevers' ran 81 - 83 mph. I've seen two different serial number Performance Reports for 29's with 600's and they were right at 83 mph. Those were the one's with the anchor locker and ladder, and they were heavier than the earlier stepped hull 29's by a couple of hundred pounds.

I was thinking about building my 500EFI into something a little more. I have seen various threads with people getting 600+ from rebuilding the 500's, like I said just kicking the idea around.

29 Fever easily can reach 80+ with 600 sci with no problem!!!

My 05 29 with 575sci and scx/sc drive runs 80+ and is bullet proof. (for sale in the classifieds) I would worry about your drive with 600hp.

600sci with Bravo XR is bulletproof as well.
I had this combo 5 years no motor or drive issues.

The boat can get there if you're mapped correctly with a 525 and the conditions are optimal.
Over 80 you better make certain you're on top of the tabs & trim.

With the last prop I tested I got my 29 with with an Ilmor 625 to do 81mph and that's with 27 prop slip. We're still trying to get it dialed when I have time but I'm still hoping for at least 85 or so.

I'm thinking this year I will end up rebuilding my engine, expecting to get high 70's with my single step 29 but hoping for 80.

My 27’ fountain with a 600hp stroker goes about this fast with my wife riding shotgun. 60 plus "I hate you" 70 plus "your never never getting laid again" 80 plus I didn't hear anything... Weird... Coast guard said she was really mad at me about 4 hours later. I stayed at a buddy's house.. Just to forewarn ya!!

Does anyone look at the dates on post before commenting? Just asking.

Yes it will mine has a 540 NA and does 84 gps and we are still testing props. And that is with full tank of gas (135 gallons) and all stuff still in boat and water tank about 1/4 fuel. Before you go crazy I know it will go faster will less fuel ( and my engine builder has already complained about me filling it up ) but I wanted true numbers cause that is how I keep the boat.

not trying to hijack the thread, kickin32 did you just 540 the bottom end of your hp500 or did you go with aluminum heads and the different cam?
im curious because we have two hp500s, one going in a 29 and one going in a 27 and a 540 has crossed our mind instead of a blower

540 bottom, custom cam, Brodix bb2x heads, Brodix intake, dominator 1050 carb. Would have liked to do a blower but too many of my friends eat drives and that gets costly.

Spinletto I was wondering how you were making out with that new IImor motor. I hadn't heard much from you since you started that project.

I know this is an old thread, but can I ask what propeller did you use?
I have an 29 fever with a MCM-HP500, upgraded to 548 (602 hp at 6000 rpm) But the speed is about 69 mph. with a 4 blade bravo one 15 1/4 x 26p (5300 rpm) If I trim more the rpm increase, but not the speed.

New test yesterday with new spark plugs. Got 74 mph. at 5400. trimmed out, but can not get more than 5500 rpm.

I was running a hydromotive 28 left 4 blade
Now we are messing with a hydromotive 27 left with a 5 blade

Ok. The sterndrive broke last week. Before it broke I actually got 76.8 mph at 5600 rpm. Best speed measurement I've had. But I think and hope there is more to be gained with a little research on the propeller and gear I am considering buying Bravo 1 XR sports master short. Someone who has experience with these drives of Fountain 29? I belive I have to buy 5 blade propeller with shorter drives. Hoping for a little more speed and increased stability. What do you think?

Do you know what your x dimension is?

I'm not quick 600hp but I'm going to chime in here. Mine dynoed at 585 hp with a brand new xr drive. I live in the northeast and run fresh water. So far with a stock 28p left hand I have run a best of 78.4 at 5100 in good conditions, 2 people and light on fuel (132gallons full). My cruise at 3600rpm is around 50-53 mph and at 4000rpm 60-61mph. The slip numbers for this prop is really good, but I just can't quite spin it at WOT, I need to be around 5300rpm. I've tried a couple different recepies from bblades, but we are still trying to dial it in. I ran a best of 80mph at 5400rpm but the problem is the cruise. I loose almost 8mph at 3600 rpm. I realize I will have to give up a little at cruise to gain it on top but not 8mph! Any ideas? With 585 hp should I be able to run 81-82mph with 10% slip? It does run that percentage with the stock 28p. Everyone on here with 29s say they run low 80s with a 575sci engines.

I have a 29 with a 548 pushing 635 at 5400 running an IMCO -1 shorty. I have seen 82 both with a labbed 4 blade 30 Bravo 1 at 5500 and labbed 5 blade 28 Maximus at 5200. I still think I could get closer to 85 if I spend more time tweaking both props.

Had the same happen to me on my 27 with 600 hp with a labbed 26 from b blades it's crazy but I can't brake 71 with a 24 p5x hydro at 5300 and 70 with a stock 26 at 5100. Brett worked with all summer couldn't make it work a labbed 26 put me at 46 at 4k with a stock 26 at 4k at 56 the hydro px5 made a huge improvement in ride and I Cruz at 52 at 4k so ya I was hoping to see 78 but nope disappointed had a few motor issues so have to see what happens this year

I would think if you had a true 600hp you would be running at least as well as I do. Also if you are still stock x dimension and bravo drive, I would think a 4 blade would be best for WOT speeds. You should be able to run an average of 15% slip at cruise with the right bravo1 4 blade.

Slip
With a bravo 1 24 4 blade at 4k 52 14% slip
Bravo 1 26 4 blade 4k 56 8 % slip

Was your engine run and tuned on a dyno when built? What is your target rpm at WOT? What was your slip at WOT? 1.5 gear ratio? I would think with a 600 hp would be spinning the hell out of a 26p bravo1. For instance my boat came with a stock 26p bravo 1 prop from fountain. With my stock 500efi I could spin it 5200-5350rpm depending on conditions at WOT.

It was put on the Dyno three pulls and left it the way it was based on horse power and air fuel ratio tried a 950 didn't make things better or worse

Target rpm 5800 never got there in the boat
Wot
24 bravo 5500 73 Slip 12
26 bravo 5100 70 Slip 16
Px5 hydro 5 blade 24 pitch 5300 71 Slip 14

Here is the problem i'm on the borderline what 600 when the motor goes in the boat and the exhaust is added I'm losing 75 hp 50 horse power from Dyno to mounting in the boat 25 horse power is being lost in the exhaust manifolds risers are dry wet at the tip

So I need to invest into a very good set of aluminum heads like dark pro ones and upgrade to a 1050 that combination along with the short tube headers should give me an additional 80 hp

I would try a 22p bravo 1. Get the rpms up and boat may run a bit faster. However Im curious if you have a 1.36 gear ratio.

That sounds like a lot of money to get back to your 600hp. Do you have any dyno sheets. Maybe the guy running the dyno didn't have a good correction factor so the number were inflated.