Header Question

[Explosive]

I've been looking at what I need to get my 4.0L going. It's on an engine stand right now, are headers worth the money ? What set do I need ? They have a set for a b2 with a 2.9l and an explorer with the 4.0L But I'm going to have a b2 with the 4.0L and I want to be sure they fit correctly. Any recommendations? Are they worth it?

 

[Little X]

They don't really provide any power gains (the stocks are designed surprisingly well). If you''re taking it to the drag strip and looking for every last little bit of power, then a set of $500 headers might net you 3 hp, but for all the average joe's out there the stock are just as good.

 

[Explosive]

Yea, I figured it could only be 5-10 hp at best. Seems they are all shortys. I have zero experience with the 4.0L's.

Small blocks are my thing,

 

[88BII got it for $250]

They don't really provide any power gains (the stocks are designed surprisingly well). If you''re taking it to the drag strip and looking for every last little bit of power, then a set of $500 headers might net you 3 hp, but for all the average joe's out there the stock are just as good.

Every thing I have ever installed headers on(from SBF's to ATV's) has proven worth the time and money.
THE SOUND ALONE IS WORTH THE $250-$350 YOU WILL SPEND ON A SET OF HEADERS! but I guess thats just the gear head in me...
And I have always noticed a gain, mostly in the top end but still a gain.

 

[Little X]

Every thing I have ever installed headers on(from SBF's to ATV's) has proven worth the time and money.
THE SOUND ALONE IS WORTH THE $250-$350 YOU WILL SPEND ON A SET OF HEADERS! but I guess thats just the gear head in me...
And I have always noticed a gain, mostly in the top end but still a gain.

Have you ever installed a set of headers on the 4.0? Because I have, and this particular engine is what I'm basing my opinions on. I agree, on several, maybe even most engines, it's worth it. But not on the 4.0.

 

[adsm08]

Yeah, don't bother with headers, just get the stock manifolds.

The breathing systems (intake and exhaust) on the cologne engines were designed really really well by Detroit and the aftermarket hasn't really been able to do much to improve on it a whole lot.

For a DD it isn't worth the money to go buy some expensive headers for the 4.0.

 

[BeefStew42791]

I'm gonna say get the headers, and here's why..

yes your not gonna add 50+ hp like you would on a smallblock v8 BUT there WILL be a gain in your hp and torque as your flow WILL be better, even marginally. Your engine will also burn cleaner and your mpg will improve (assuming you also get a decent catback system somewhere along the lines). Now, yes the stock system is ok and will do pretty well for these engines...BUT in the back of your mind will always be the thought, "ya know..if I had just put the couple extra hundred towards headers I could have even BETTER then what I do" and it'd have been at pretty much the same amount of effort. At that point though you'll have to do 3 times the work (possibly 4) if you decide to rip out the stock manifolds and get headers then. At this point, with the engine out is the time to make your decision because your gonna make more work for yourself later.
oh and also if you decide to get headers later not only would you have paid the price of the headers but you'll also have already bought manifolds.

 

[TheOne]

and i dunno about the 4L but the 2.9L's crack and break alot so why not upgrade? cause nothings worse then getting those things off when its installed in ur engine bay!

 

[adsm08]

I can't remember ever seeing a 4.0 manifold break on its own. Doesn't mean it doesn't happen, I just haven't seen it yet.

Beef makes a good point. If you do buy a good set you won't regret it. If you don't buy them now and decide to go get them later you will regret not doing it now.


@TheOne, you are thinking of the cylinder HEADS, we are talking about exhaust HEADERS. Close, but very different parts.

 

[88BII got it for $250]

No hes talking about cast manifolds. and he is right the 2.9ls do crack out alot of the time it is the passenger side. And man ALL cast manifolds will crack out over time.
Get the headers, or save yourself a few bucks and wish you did get them.

 

[bonedoc]

I agree, with you guys. I don't know about the 4.0 but the manifilds on the 2.8 and 2.9 all cracked...not a matter of if but rather when! Go for the headers...I put them on my 2.8L and it definately made a difference especially with a 2 1/2 inch exhaust. Not to mention for my application...try finding replacemement factory manifolds!

 

[adsm08]

I'll take ya'lls word for it. Never seen a 2.9 manifold crack.

Mine are both original with 190K and no cracks.

 

[Yellowsplash]

The stock manifolds on an OHV are log style and they dont flow real well...period.

What prevents the motor from gaining much power is the exhaust port size and design. The 4.0 was built to be a torquey low rpm engine. Your not going to gain a shit load of power when you install headers alone...there are more bottlenecks in the system. With that said, headers are a great upgrade (and supporting mod if you plan to actually break into the engine to make some power), but be realistic... Dont expect a miracle from the headers alone. I HAVE them, and I love them.