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-   -   Headers on a 496 HO (https://www.offshoreonly.com/forums/general-boating-discussion/357513-headers-496-ho.html)

Monaco20 11-05-2018 07:41 AM

Headers on a 496 HO
 
https://cimg6.ibsrv.net/gimg/www.off...b643705ff2.jpg
https://cimg7.ibsrv.net/gimg/www.off...27761fe908.jpg

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

boatfreak 11-05-2018 11:12 AM

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.

BUP 11-05-2018 06:49 PM

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

SB 11-05-2018 07:05 PM

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

Zach F100 11-05-2018 11:55 PM

I counted 44 hose clamps on this set of headers.
There must be a better way...

Griff 11-06-2018 01:24 AM

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

Monaco20 11-06-2018 03:13 AM

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

Monaco20 11-06-2018 03:15 AM

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

Monaco20 11-06-2018 03:17 AM

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

Monaco20 11-06-2018 03:19 AM

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


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