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-   -   lets talk 271 fastech mph (https://www.offshoreonly.com/forums/formula/248580-lets-talk-271-fastech-mph.html)

cobra860 02-07-2012 08:16 PM


Originally Posted by cobra860 (Post 3481187)
Well I have a 1993 271 sr1.

I have installed a 540 whipple engine. 830 Hp.

I run a bravo xr 1.50 and are into testing propellers,

I run now 80 miles, at 5500 rpm, with a bravo1 28 pitch.

The problem is now that the boat bounces from side to side and get really uncomfortable to drive.

So I am wondering what to do..

This winter, the boat is taken apart, the transom was pretty rotten so most of the plywood in the transom was removed, now the transom is like new again. I am going to lift the x dimensions up 3" for the transom, montage 280 k planes and lantham double ram steering. So I hope the boat will not do the chine walk. The boat has also going thru a diet.
I think I can lighten the boat for aprox 250 pounds or more. Time will show how much I can remove without sacrifising the comfort of the boat.

adam12981 02-24-2012 09:58 PM

jwurl- what kinda prop are you running and what are you slipage numbers? BBlades is doing some work on my prop trying to get slipage down. I am around 18% now. The boat runs very flat on the water, I would like to get some bow lift. Do you have that problem at all?

jwurl 02-26-2012 10:05 AM

I am currently running a box stock 28p Bravo 1 four blade. I know for sure i need to move to a 30p because it runs out of prop. I have no problem with bow lift. If anything it is to much because the boat walks like crazy at top speed. I heard your boat did 83 GPS with a full tank of fuel and 4 people on board with the previous owner???? Jeff Wurl

adam12981 02-26-2012 06:56 PM

I was told that also, if i can get the slippage down to 14-15% its possible. It has not done it with me driving, hopefully bblades can put the prop back to what it was before. We will see. My boat tends to walk a lil above 76, I can use tabs to control it but they always ends up slowing me down. I will say that full tank of fuel and 4 people or 2 it still runs the same speed, solid 77 best i have seen is 78 gps

speedydivers 06-22-2014 06:55 AM

I have a 1997 271 fastech 454mag mpi with a 23 pitch prop she does 60 at 5000rpm just feels like it should have a lot more get up and go

bj1464 06-22-2014 09:32 PM

I own 2005 271 with 525 efi it's a heavy boat , I agree at times need more get up and go.

Pave 06-23-2014 08:56 AM

2002 271 496 mag ho record is now 51,4 knots gps (5200 rpm) which is for about 60mph.

CaribouLou 06-23-2014 12:19 PM

I have a 98 with a 600hp 496 stroker, XR/-1, with a Scott baker/hering 28 bravo. Hope to see 75, will probably only go 50.

racinfast002 06-24-2014 07:52 AM

99 with a 502 Mag and 26P prop on it, get about 63-64 on the phone GPS. If you bought it run, you bought the hull. There are faster 27' boats out there, but I think you would be hard pressed to find on with all the ammenities of this boat and run faster.

speedydivers 06-24-2014 03:07 PM

I don't suppose that there would be any noticeable change by replacing the exhaust manifolds with something like EMI thunder exhaust ??
has anyone had any luck with changes like that ?


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