Headers are they worth it

[Rbcconst]

I have a 496HO in a Lavey 2750 and thinking about the Dana headers. Is it worth it? For anyone that’s done it what improvements did you see and did you have to change to a bigger prop


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[farmo83]

My dad put them on his boat and it was much more responsive. As far as top end it wasn't earth shatteringly different but it was a bit quicker. As far as props yes he went from a 22 that he had repitched to a 24 to a true 24.

 

[footer]

I switched out a set of stock Merc 454Magnum iron exhaust manifolds for some stainless Hi-Tek tubular headers on a Hallett 210. My goals were to lose some weight in the rear of the boat to make the ski wake better (I also removed one of the batteries), make it sound better, and maybe get a little more top end speed. All those things were accomplished, although my wife would argue the sound improvements. I saw 3-4 more mph on top end, all from RPM, because prior to the headers the engine wouldn't swing the prop to recommended redline. 120 fewer pounds in the back of the boat helped the speed, too, so it wasn't all due to the headers.

What I really learned is that you can't expect a lot of change just from the headers, because the engine won't make a lot more power just being able to exhale better. It also needs to inhale better. I saw a LOT more power, at every RPM, when I changed the carb, intake manifold, and cam a year later. The intake volume better matched the exhaust volume. And then I could go up a prop size, while keeping the holeshot I wanted, and added almost 10 more MPH on top. What I wish I would have done is listened to my engine guy and done a stroker kit with more compression at the same time. But I sold the 210 the next year and got a wake boat for the family. Someday...

 

[ToMorrow44]

I’ve installed a few CMI sport tubes on 496s, never any Dana’s though. Typical gain for the Sport Tubes was 3-5mph on the top end. Some will argue $6k for the CMIs isn’t worth 3-5mph, some will.

CMIs and the reflash from Whipple would probably work very well on your Lavey.

 

[Rbcconst]

I’ve installed a few CMI sport tubes on 496s, never any Dana’s though. Typical gain for the Sport Tubes was 3-5mph on the top end. Some will argue $6k for the CMIs isn’t worth 3-5mph, some will.

CMIs and the reflash from Whipple would probably work very well on your Lavey.

Sounds like it may be worth it. The Dana’s aren’t nearly as expensive. There was some dyno testing showing the Dana’s produced almost the same HP increase.

How does the flash effect the motor? It has 500hrs on it. Almost half of those hours are idle hours.


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[ToMorrow44]

Sounds like it may be worth it. The Dana’s aren’t nearly as expensive. There was some dyno testing showing the Dana’s produced almost the same HP increase.

How does the flash effect the motor? It has 500hrs on it. Almost half of those hours are idle hours.


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You get a little more power with the Whipple reflash but they can also help clean up the super rich idle that Mercury likes to run.

https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=52

 

[Mike K]

I didn't have Dana's but I did buy CMI's. Yes they are worth it. I had a 496 in a Eliminator 25. I spent $6000 on CMI headers, tailpipes & install ... huge gain in power ... big investment but the difference was soooo worth it. Cheapest and most reliable gain of 50hp... as compared to a whipple or procharger.

 

[DSMITH]

I had the Dana headers on my old 25’ Shockwave 496HO. They’re not exactly cheap but I would say they’re a good addition to the engine. With the headers the boat ran a size larger prop labbed and worked really well.


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[Singleton]

You get a little more power with the Whipple reflash but they can also help clean up the super rich idle that Mercury likes to run.

https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=52

I had the Whipple stage 2 flash done. The soot was worse at higher RPM then stock. Whipple runs a very rich setup, and end result is more soot at higher RPM’s.
Also, I was changing engine oil every 20hr due to how dirty it got and plugs every season. In the end I went back to the normal setup and reduced the soot and more importantly the soot tracked over the engine hatch that was always on the swimstep

 

[Rbcconst]

I had the Whipple stage 2 flash done. The soot was worse at higher RPM then stock. Whipple runs a very rich setup, and end result is more soot at higher RPM’s.
Also, I was changing engine oil every 20hr due to how dirty it got and plugs every season. In the end I went back to the normal setup and reduced the soot and more importantly the soot tracked over the engine hatch that was always on the swimstep

That’s interesting, the claim is less soot. I can see how that would be aggravating.

I’m not sure this is a mod I would go for as you have to run 91 but the hp gain isn’t much. Also sounds like it would take some of the longevity out of the motor tuning it to the max.


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[Rbcconst]

I had the Dana headers on my old 25’ Shockwave 496HO. They’re not exactly cheap but I would say they’re a good addition to the engine. With the headers the boat ran a size larger prop labbed and worked really well.


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That sounds like a win!


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[96motorhead]

I would look at lightning headers over CMI. They have two types, one has a stainless inner and steel outer tube. The other type is full stainless. Both types are significantly cheaper than CMI.

 

[ka0tyk]

I bought a set of merc "S" pipes and the dude tossed in the stock steel manifolds as well. I had no idea they weighed so much in comparison to my alum center rise. I think for sheer weight alone it'd be worth it.

 

[Singleton]

That’s interesting, the claim is less soot. I can see how that would be aggravating.

I’m not sure this is a mod I would go for as you have to run 91 but the hp gain isn’t much. Also sounds like it would take some of the longevity out of the motor tuning it to the max.


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Yep. Online claims less. However when I called to complain, I was getting more not less; I was told at higher RPM’s (anything over 3500), you will experience more soot due to the calibration.

Don’t get me wrong, loved the acceleration increase I got out of it, but family boating with kids requires a ton of jumping off swim step and the dirty feet wore me out. Best thing I did was not reinstall (plus it was going to cost $$ to reflash my ECU after it was fixed).

 

[LargeOrangeFont]

Yep. Online claims less. However when I called to complain, I was getting more not less; I was told at higher RPM’s (anything over 3500), you will experience more soot due to the calibration.

Don’t get me wrong, loved the acceleration increase I got out of it, but family boating with kids requires a ton of jumping off swim step and the dirty feet wore me out. Best thing I did was not reinstall (plus it was going to cost $$ to reflash my ECU after it was fixed).

I’m assuming you have above water wet exhaust exits?

 

[Singleton]

I’m assuming you have above water wet exhaust exits?

Yes, below the swim steps. You can see swim step brackets and exhaust location in pic when I had steering uograded

 

[LargeOrangeFont]

Yes, below the swim steps. You can see swim step brackets and exhaust location in pic when I had steering uograded

Yea I can see the soot being messy with that setup.

 

[Rbcconst]

Yep. Online claims less. However when I called to complain, I was getting more not less; I was told at higher RPM’s (anything over 3500), you will experience more soot due to the calibration.

Don’t get me wrong, loved the acceleration increase I got out of it, but family boating with kids requires a ton of jumping off swim step and the dirty feet wore me out. Best thing I did was not reinstall (plus it was going to cost $$ to reflash my ECU after it was fixed).

I’ll pass on that. I cruise higher then 3500 and I am assuming so do most with a 496. Add the 91 fuel and that seems like a looser for small Gains.


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[Singleton]

I’ll pass on that. I cruise higher then 3500 and I am assuming so do most with a 496. Add the 91 fuel and that seems like a looser for small Gains.


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Don’t forget the additional maintenance. I used to do 1 oil change a season, after the upgrade that moved to oil changes every 20-30hrs (so 3 a season for me) and new spark plugs every season.

Going back to stock was actually a smart $$ decision. If my ECU did not crash I would still have it. But to be 100% honest I was thinking about removing the ECU stage 2 prior to the ECU failing.

 

[02HoWaRd26]

Let’s be real it’s all about looking good and sounding good! The Dana’s did both of those.
You and i have spoken in depth to my thoughts and i would definitely do headers again, the tune idk but the headers YES, the cruise power is where i found the real gains top end i saw 2-3 but that was the increase in limiter and power to spin bigger prop.
They look great tho and sound so much healthier even though mine sit 70% below the water line.

 

[Rbcconst]

Don’t forget the additional maintenance. I used to do 1 oil change a season, after the upgrade that moved to oil changes every 20-30hrs (so 3 a season for me) and new spark plugs every season.

Going back to stock was actually a smart $$ decision. If my ECU did not crash I would still have it. But to be 100% honest I was thinking about removing the ECU stage 2 prior to the ECU failing.

That’s a lot more $ in maintenance. It’s not cheap to get that stuff done.


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[Rbcconst]

Let’s be real it’s all about looking good and sounding good! The Dana’s did both of those.
You and i have spoken in depth to my thoughts and i would definitely do headers again, the tune idk but the headers YES, the cruise power is where i found the real gains top end i saw 2-3 but that was the increase in limiter and power to spin bigger prop.
They look great tho and sound so much healthier even though mine sit 70% below the water line.
View attachment 731540

I think I’m sold on the headers. Definitely not sold on the tune. Lol
However the 3mph on the top end would be nice but I may only ring the boat out like that 2-3 times a season. I can see why people would want to do the tune, it’s cheap performance.

They sure look nice on yours!!


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