Baja_man

I have heard of the CMI issues with the 05-06 Sport tubes for the 525's but have there been any issues with the sport tubes for the 496? I know recently CMI has made an E-top model for the 496 with no tails but I am more interested in strictly the Sport tubes with tails for 496.

Irishtornado

They aren't having issues. Steve has had his 3yrs now with zero issues.

bajabob

they get cracks .to many headers have got the same thing wrong with them .red flag . i look in to them .didn t like what i came up with to many guys got cracks in them. nice looking not worth the money for me . good luck . i got stainlless marine headers had them for 20 years and very happy with them

Raylar

We have not heard of a lot of cracking issues with the 496 SportTubes that CMI makes for the 496 and they do make good power increases about 30-45HP depending on the engine HP and upgrade levels. I will caution you though that there have been a few 496 SportTube users who experienced some exhaust water back on rear cylinder valves and cylinders due to the situation of almost no tail length when used with switchable exhaust on the boat or tight exhaust routing for S-Tubes under integrated swim platforms and some corner exhaust exits that use added elbows and corners.
I think you may be able to get some first hand feed back here on OSO if you search 496 CMI SportTube headers.
I do not believe that CMI has the cracking and leaking problem here they appear to have with the Mercury Racing versions on those certain year HP525EFI engines.
Hopefully some other OSO'ers can shed some direct experiences here on the Mercruiser 496 and not the whole breadth of engines.

violator

I have 4 seasons on mine with no broblems.

ZP'd

496? Just leave it alone seriously unless your doing a bunch of upgrades. Alone you not going to notice that much if any difference and you WILL run the risk of reversion. The 496 is a awesome turn key motor until you try to "partially" make it more then it is. I personally no of one motor that had reversion issues with CMI headers on a 496. Cost him a new motor.

Baja_man

No diverters, straight back. I am just torn between Dana and these CMI's.

Baja_man

Yes, am doing some engine modification.....have to put headers on now.