600 hp 271 how fast?
 

Who has the most hp in a 271?
I just got a 600 hp Volvo, for my '97 271, and Im wondering how fast it will be. Stock with the 415 it averaged 64 with a top of 66. After adding lightning headers, K&N, bumping fuel pressure I saw 66-67 on average with 70.2 as a best ever. Then beefed up to 509 (brodix heads, crane cam, roller rockers remapped ecm etc.)about 500-525 hp (stock efi intake hurtt me) and saw around 70 the first time I ran wot, but a series of mishaps kept me from wringing her out.
I have an article on a non stepped 271 with a 542 Ligenfelder (bad spelling) that went from 63 with stock 415 to 75 and change with the 542, so I figure add the 60 hp, and the couple mph of the stepped hull and I should just come up short of 80mph. Any input on this
Steve:D

I'd say your in the ballpark with that estimate.

Does your 600 have Eickert headers, and are you using the DPX drive, or a Bravo?

I can tell you that a whippled 502 will run 81-83 on fresh water depending on conditions. I believe that whipple claims around 640hp with their kit...so your 600hp should be in the same range.

I am using the bravo with this engine, i posted in the Tech section with more detail

Ok, next question...... I am looking into a few options for drives etc. C_spray recomends the volvo drive as he has had no problems with the set up in 2 different boats. I like the idea of the duo prop as the boat leans from prop torque, and this will settle most of it down. Not to mention a much better hole shot as this thing was a real dog out of the hole. I am also concidering the ITS to add on, as I feel the extension may also help with the torque, and improve performance overall. Will the x-dim need to be changed? And can I use my std bravo hp with 20 hrs or do I need the xr?
Any one have the ITS on a 271? or another ext box
Thanks

I had a stepped 271 with the Lingenfelter motor in it (541 hp.), boat had full Latham steering and K-Planes and it was a handful above 75mph. Formula put a 1.65 Bravo HP drive on it, not a great idea in my mind - should have been a 1.50, and I was spinning a 32" lab-finished 4-blade, turning 5,800 rpm. Personally I think that is too much hp. for that hull, but that is just my opinion. Boat had a tendancy to chine above 73-74 and was not happy if you pulled out of the throttle too quckly. This didn't however sway me away from Formula all together as I have been considering going to a 292 with the 6.2's, (or whatever model they my come out with to replace the 312 in the near future... anyone hear anything on this yet?).

I think that Formula makes a quality product, just don't ask them to think too far "out of the box" as their success in this area is limited... just my .02:)

Merkruzer -

How do you like the Lightning headers? Would they fit the stock 4" exhaust hoses to the Silent Thunder exhaust system?

The lightning headers were great but they will have to be custom fitted to the existing holes. The stock system has the 3 inch risers in them so I ordered the headers 3 inches taller. The headers were about 1-1/2 inch too high, lightning exchanged them (for a small fee) for stock bravo opening, as I opted to delete the mufflers.

chase910

how did your buddy's boat run at wot, was it a hand full or was it pretty stable

It is very stable, actually I was quite shocked how stable, especially seeing how he's basically running the stock steering. He added a sidewinder steering for safety, but that is basically a shock adsorber. There is no chine walking even at 80.
The boat is a '98 Fastech bottom. I believe the hydromotive prop helps as it provides stern lift and thus keeps the boat running quite level at high speed. As a matter of fact he outruns faster boats in the rough because the boat runs level while others are flying out of the water.
We tried a 30 merc labbed Bravo1 which ran the same speed as the 28 Hydro, and while the boat got on plane better it also ran with more bow lift and would launch on bigger waves where as the Hydro kept the boat more level.
One other note, we tried a right hand 32 Bravo and the prop would just cavitate with any power put to it. Do these boats have to run left hand props? I figured the prop blades were providing too much stern lift thus the cavitation.
The only thing I don't like about the Fastech bottom is the tracking. The boat can be blown off course by the wind even at cruising speed, but its stable at high speed.

In addition to my above comments, I also believe that the 1.65 drive and the 32" prop. had something to do with the handling. If I could have run a 1.50 drive and a 28" or 30" prop. I think it may have calmed the boat down a bit, I also never played with the X dimension on it, so I have no idea what it was or what it would have been like had I dropped it or raised it via spacers. I hope you have good luck with the set up, I did like the boat and it had amazing mid-range punch, it just needed more time then I was willing to give it to be set up better. On to the next boat...:D

That's what we found as well, we couldn't get a prop to work right with the 1.65 drive. Swapping to a 1.5 thus running a smaller prop solved the problem.

Troutly, I think the tracking issue is a direct cause of the ventilation of the hull. I guess its showing there is air being introduced along the bottom which is why it has a slippery driving effect. I guess its a trade-off for the high-speed stability. Pad bottom boats, such as a Velocity track as if on rails, but will chine walk at high speed.