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Discussion Starter · #1 ·
the addition of HO cams and headers? I currently have a MagnaFlow muffler and drop in K & N filter with the rubbber flap removed as well as the intake arm leading to the airbox.

I'd like a little more bottom end "umph" if you know what I mean. Would the addition of HO cams as well as headers give me a significant gain in this area? And how will this affect mileage and the emissions? Any suggestions and help are appreciated. Thanks.
 

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The addition of the headers and cams will wake it up quite a bit. Headers will not hurt you on emissions and you should pick up a few more miles to the gallon. The cams will not hurt the emissions if you stay with the factory HO set up but they will drop your fuel mileage some.

The best headers would be the long tube going into duels. You can go with the short tube headers and stay with your current exhaust system and still see a good improvement.
 

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Discussion Starter · #3 ·
Mopar RT,

Thanks for responding! With regards to the long tube headers, who makes it for the 4.7L Durango? I know Doug Thorley has an application for the 4.7L Dakota but not the Durango. I'm muffed by this in that you would think that both trucks would almost be identical in the undercarriage, right? Unless, the Dakotas have their cats further back or lacking the pre-cat that the Durango has. Either way, a mod in the exhaust system would stil be required if I were to go with the long tube headers. Also, how much work is required to install the headers, that is, the shorties if i were to go that route? Thanks again!

Joshua
 

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Don't jump you gun...A wide open exhaust can do a lot to ruin your low end torque. With the use of large headers and exhaust you lose back pressure which in return get you better gas milage but decreases you low end torque and make the truck unload near 3000rpm vs. off the line like you seam to, and I want.

A local exhaust shop should be able to give you ideas and be able to rig up a custom exhaust to maximize low end torque. Or you could give the guys here a couple day to start throwing in their two cents...Ussualy two opinions aren't enough when it comes to exhaust.
 

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What gears do you have right now, and how tall are your tires? I have the HO cams and I am going bigger. The cams are ok, but I wish I would have gone bigger from the start. Depending on your gear setup that might be a better place to start. A Superchips programmer or a custom flash will help wake up your 4.7 also :banana2:
 

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Discussion Starter · #6 ·
Baby Hemi said:
What gears do you have right now, and how tall are your tires? I have the HO cams and I am going bigger. The cams are ok, but I wish I would have gone bigger from the start. Depending on your gear setup that might be a better place to start. A Superchips programmer or a custom flash will help wake up your 4.7 also :banana2:
My gear set up is stock at 3.55 and the tires I'm running are 275/60/17 on R/Ts. I'd like to keep my current gas mileage or better but would also like a little more low and midrange power. Is that possible?

With regards to Superchips and custom flash, I'm new to that. Can you explain that to me? What are the benefits and will it affect emissions as well as mileage?
 

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I am sure there are some experts on here that can give you a better explanation than me about some of these parts. Your 17" wheel and tire combo is heavy. Gears would put less strain on your motor to get your vehicle moving and actually provide better gas mileage around town. I would go with at least 3.92 but preferably 4.10. I am trying a new gear/ tire combination this weekend and can give some better info later. Check this out http://superchips.com/product.phtml?p=15&mmk=441&msg=+ . This should help a little. A custom flash is more taylored to your specific application though ie: Bigger cams, Supercharger, Turbo etc.
 

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Bryan said:
Don't jump you gun...A wide open exhaust can do a lot to ruin your low end torque. With the use of large headers and exhaust you lose back pressure which in return get you better gas milage but decreases you low end torque and make the truck unload near 3000rpm vs. off the line like you seam to, and I want.

A local exhaust shop should be able to give you ideas and be able to rig up a custom exhaust to maximize low end torque. Or you could give the guys here a couple day to start throwing in their two cents...Ussualy two opinions aren't enough when it comes to exhaust.
Back pressure is an unfortunate by-product. Full length headers will help your bottom end but shorties will do nothing to hurt it.

Backpressure, the MYTH
 
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