Just bought boat last week, repowering it and was going to install a brand new set of CMI's that i just bought for my baja, but they are way off. throught that i needed 3inch plus on the 271 but it looks like its 5.5 inches higher than the standard bravo holes like my baja.....what are people running for headers on the 94's. I also have a set of stainles marine manifolds, but i wanted an exhaust that made some power with the 575hp na i am building.

guy to talk to is rattle snake jake he had cmi s and all in a 271 good guy to talk to he will tell all you need to know

The 271SR1 uses a 6 inch elbow riser in the stock exhaust set up to get the correct tailpipe down slope. It is because of the low X diminsion in relation to the Silent Thunder location. So to answer your question... about six inches higher than a normal Bravo set up. I had CMI make a set of E-Tops for my 271 and it's not an off the shelf application. I also ordered the stainless distribution tube option and had to shorten the rubber 90 degree connection pipes to keep the tubes off the top of the stringers.

I think Rattlesnake Jake had a 271 Fastech. With their step in the hull, grid stringer system, and notched transom, their X to exhaust outlet distance is different than a SR1.

thanks, man thats what i was looking for!!!
How many hp was yours and what was your set up and speeds....

I thinkim going to go with stainless marine exhaust since i all ready have the manifolds......called today and they can make me custom long tail for 800-900 a side, still cheaper than the cmi's.

I installed Keith Eickert headers on my 271 Fastech. The tip holes on the transom are located in the wrong spot because of the silent thunder box. The only way to get the CMI's to line up correctly is to get a custom tailpipe. Since I could not get a custom tailpipe on my Eickerts I ended up cutting new holes and filling in the old ones. I can send you some pics of what I did if you send me your email address. Jeff Wurl

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It's a stock 575SCi that is supposed to make 550hp at the propshaft. The drive is a 1.5 XR. Most of the time I use a Mercury Racing labbed 26p Bravo that spins right. When the weather cools off (the 575 runs noticeably harder in cool temps), I will sometimes switch to a non-labbed 26p Bravo to keep the motor off the rev-limiter and improve the mid-range cruise speeds. Both props have run about the same speed which is just shy of 74.

My only complaint is the prop torque with the non-labbed Bravo at my usual 3500-4000 rev cruise speed. It will make the boat list to port if I am carrying a passenger. Depending on the size of the passenger, I might have to drag the port tab. The labbed Bravo is much, much better at providing a level ride at cruise speeds. One of these days I am going to round up a Mirage Plus to try. Not because the three blade might be faster, but in hopes of reducing the prop torque.

My wallet put a stop to the project, but I am curious if a shorter lower would help. Besides having lots of props to test, that is the only thing I'd like to try.

Make sure you've got good steering. It can start to get loose over 70...