Hi guys
I need to change my manifoils and raisers on my 2009 496 HO
I have got a very good offer to buy these used headers (see photo)
They have been on a 496 HO before same type of boat Formula 271 SR1 before
I am going to pressure test before buing of course…
Anyone know which brand7producer it can be ?, no logos on the headers
What kind of performance benefits can I expect compare with the stock exhaust ? more hp, higer top speed etc..

Greetings from Oslo, Norway

I'm guessing you will get a wide range of answers but I put CMI sport tubes on my 496 several yrs ago when they first came out and while the looked cool and even sounded better I didn't see any performance gains.

ZERO to 3 mph MAX gain would be a winner at best if even that ---- with the install stock app to stock app.

Vortec 8100 / 8.1L / 496MAG Mercury Marine Performance Parts Upgrade - Raylar Big Power

Old CMI split top headers with a short homemade welded on tail.

Well at least better sound and a lighter boat :-) Thanks for the reply Boatfreak

Thanks for the reply BUP :-) I am trying to reach 65 mph, so what you telling me can get me there ;-)

Thank you SB ;-). Very intersting article, I thougt that the 496 HO had 425 hp at the prop shaft ….

ZAC F100 I did the same ;-) Very interested to hear suggestions how to doing it another way, safe and with out leaks :-)