DANA marine vs. CMI headers
 

which headers are better for a 496HO? Dana marine seems to be the better choice to me but there are a lot of people running the CMI headers.

cmi's sure look beautiful but you will start a war with the question which is better, both claim gains accross the board and alot of people who bought cmi's claim no gain after dumping 4-5k, dana's offer similar gains and are alot less, i've personally had dana's on my baja hammer with 7.4 mpi 310hp and i can say i had real world gain, rpm's went up about 200 and i went from a 23p to a 25p and was staying in the wot rpm's speed gains were about 2-3 with exhaust and prop change, i'm considering cmi's myself but know how nice the dana's are, curious to here other feedback aswell

My buddy has the dana's on his 496 and because of the water flow if he ran it hard for any period of time it would send the motor into guardian mode. I don't remember what he did but he had to something inside the riser to correct this. He told me he wished he had paid the extra money and got the CMI's and saved himself some headaches. Just an FYI.

I was a big tubular header guy but wanted something robust that I wont ever have to worry about. I ended up buying Dana's (2 sets). What you dont realize is that you (and most others) assume "manifold" but they are as close to a header style inside that you could possibly imagine. Each runner is individually chambered up past the riser into the collector. They are big runners and make a really nice set up that looks good and gives a performance gain. The gains are arbitrary since you might only need 12HP to make 1 MPH in a smaller lighter boat and 20 HP to make 1 MPH in a 34 foot boat like mine. The best part is they are competitively priced and you can go up to the "105" riser that is longer and bigger for relatively nothing.

In the begining of our 496 kit , we had a couple of customers that were having water sensor issues. The manifold itself doesn't get hot, we were experiencing a hot pocket where the sensor installs. It was pretty uncommon and usually only happened to boats with water pumps that were getting tired.

We adjusted the water inlet at the bottom of our manifold to correct the issue and have had no problems in the last couple of years.