I'm looking at headers as one of my next upgrades. I'm getting 4.10's, then my tuner, then headers. So, what options are there for the 3.9 v6 Dakota? Whats the difference between short and long? I cant afford a lot, so this is all a process. What are the cheapest headers, the mid range ones, and the most expensive ones? How much should i expect to gain from them? Any change in sound?

 

it would help if u said what year your truck is. if its a newer truck u dont have many options, and theyre all shortys. theres only 2 choices if 4wd and i think only3 if youre 2wd. JBA and possibly Pacesetter if youre 4wd, and JBA, pacesetter, and gibson if youre 2wd. headers really arent worth it you u dont plan on doing too many engine mods. ive got JBA headers on my 00 3.9 and they suck. i had one crack paid 300 bucks for a replacement, and had to change gaskets on the drivers side twice and ive only had the headers on for about 3 years. i noticed i lost some low end but gained some highway power, i would skip headers unless u plan on modding your exhaust and intake.

 

Don't waste time in headers its a truck not a race car
biggest gain i ever saw was 15 rwhp and that was on a chevy 1991 545 c1500
A reg. iron manifold smooth and ploished will createnear 2/3 the hp of full length headers(David VIZARD)

 

Without mufflers Steve Dulcich found a 4.5% hp gain with long tube headers.
(17 gain out of original 376)

http://www.popularhotrodding.com/eng.../0602phr_hemi/

With muffler and catalytic converters
Chrysler only says there is a less than 3% gain
when they designed shorty headers for the 6.1 Hemi
instead of the manifolds on the 5.7 Hemi

http://ask.autoblog.com/2006/02/20/a...-7-and-6-1-v8/



"Exhaust headers on the SRT 6.1-liter HEMI are individual tubes encased in a stainless steel shell. Exhaust runners allow increased gas flow while maintaining fast catalyst light-off, while adding 12 horsepower over the 5.7-liter engine’s cast manifolds."

{12 gain out of 418 hp is 2.8% and this is about the same percent as you should hope for on a V6 with cat and mufflers behind them}

 

In the most recent EngineMasters magazine on the news stands now,
(Spring 2007 on page 58)
Steve Dulcich has another good article where he tries various mods on the 300 hp 'crate' 5.9 Magnum V8 sold by Mopar Performance. This crate engine has the same pistons, cam, & cyl heads as a stock truck engine, but comes with a MP dual plane manifold.

When the crate was tested stock with factory truck exhaust manifolds but no mufflers or catalytic converter
the dyno showed:

at 4600 rpm
HP=313 Torque=365

at 2500 rpm
HP=184 and Torque=387

When beautiful looking TTI long tube headers exhausting into long collectors were substituted for the factory exhaust manifolds with no other changes, the dyno showed

at 4500 rpm
HP=325 Torque=380

at 2500 rpm
HP=185 Torque=389

The 12 HP gain at 4500 rpm is about a 3.8% gain
which is similar to the 4.5% gain Dulcich found with headers on the 5.7 Hemi.

A smaller gain would be seen if mufflers and catalytic converters were used.

Note that the gain at 2500 rpm is only 1 HP or 0.5%
Most daily driving and towing is done in the important 1500-2500 rpm range.

There is a article with pictures on installing JBA headers on a 3.9V6 at:

http://dieseltruckworld.tenmagazines...le&aid=599