4.0 Headers on a 2.9?

[TexasDuck66]

Hi there, been struggling to find a set of 2.9L headers for my 88' Ranger 2.9l '5 Speed 4WD.

I recently compared 4.0 header gaskets with 2.9s and they had the same bolt pattern and lined up perfect. Only difference was that the 4.0s had bigger holes.

Will 4.0 headers work on a 2.9?

 

[rusty ol ranger]

They might work.

But they might "rattle down" from the smaller 2.9 bolts and leak

 

[sgtsandman]

I'm wondering if the tubes are going to be too big and thus provide no benefit as a result.

 

[gaz]

They might work.

But they might "rattle down" from the smaller 2.9 bolts and leak

The header bolts kits from Stage8 are the exact same part number for both the 2.9l and the OHV 4.0l.

 

[rusty ol ranger]

The header bolts kits from Stage8 are the exact same part number for both the 2.9l and the OHV 4.0l.

Well there ya go

 

[rusty ol ranger]

I'm wondering if the tubes are going to be too big and thus provide no benefit as a result.

Im not sure youd see any benefit from headers on an otherwise stock 2.9 anyway. Unless hes just going for sound

 

[Josh B]

It don't go that fast but it sure do sound good!

Isn't there a certain amount of back pressure necessary ?

 

[sgtsandman]

It don't go that fast but it sure do sound good!

Isn't there a certain amount of back pressure necessary ?

This guy explains how an exhaust system works and why the back pressure thinking is incorrect:

 

[rusty ol ranger]

It don't go that fast but it sure do sound good!

Isn't there a certain amount of back pressure necessary ?

Ive always understood it as smaller tubes are best for low end torque on a stock motor, fat tubes breathe best at higher RPMs but if youre still sucking air through a straw on the intake side there is no reason to be sending it out through a sewer pipe

 

[gaz]

@rusty ol ranger , @sgtsandman ,

I drove my Ranger stock from 1988 until I installed headers during the spring of 1998...it MADE A HUGE DIFFERENCE!!

To attempt to graphically explain:
• driving southbound through the Suskayuu mountains 100% stock, I would lose speed climbing in OD (5th gear), need to downshift to 4th and barely making the peak @ 52 mph.
• same southbound drive through the same pass, same truck except for the addition of JBA headers; held 60 mph in 5th gear with throttle to spare. My assessment was that the improvement in torque, enabled the engine to produce more power/torque at the given engine RPM.

Definitely improved my overall driving pleasure. Also brought about the highest mileage I've ever recorded in that truck; during that round trip from San Diego to Seattle and back it averaged 28.4 mpg.

I can now never question the benefit from adding a quality set of headers. I have not measured the I.D. of the 98+ OHV 4.0l header tubes but visually there I do not see a difference. The outlet exhaust port of both the 98+ OHV 4.0l and the 2.9l heads are nearly the same, if not the same volume; it only stands to reason that the aftermarket headers for each, will be the same volume, if not extremely close. The pictured exhaust gaskets certainly demonstrate how close the 2 systems are.

The 98+ OHV 4.0l heads I had ported for the 87BII had to be opened up a bit to match the 2.9l headers, which are being used on it

 

[85_Ranger4x4]

There is more to it than the bolt pattern and port spacing.

There may be some other interference between the two engines elsewhere.

Yeah, it may bolt on the head but there may be something else hiding in the woodpile waiting to surprise you.

 

[rusty ol ranger]

There is more to it than the bolt pattern and port spacing.

There may be some other interference between the two engines elsewhere.

Yeah, it may bolt on the head but there may be something else hiding in the woodpile waiting to surprise you.

I may be talking out my ass but...

The only issue i can think of is the 4.0 has a higher deck height then the 2.9 (i believe, its got more stroke)...so in theory the heads would sit lower on a 2.9 then on a 4.0....so a bit of H pipe modification might be needed beyond what might be needed normally.

 

[franklin2]

I have never seen a description of the 4.0 having a taller deck height. I did read in a article somewhere the 4.0 was much like the Chevy 400. Lots of modifications to the block inside to accommodate the longer stroke without raising the deck height. Same modifications chevy did to the 400 without raising the deck height.

P.S. Found the article. https://www.enginebuildermag.com/2001/04/rebuilding-the-ford-4-0l-pushrod-v6/

 

[gaz]

There is more to it than the bolt pattern and port spacing.

There may be some other interference between the two engines elsewhere.

Yeah, it may bolt on the head but there may be something else hiding in the woodpile waiting to surprise you.

@85rngr4x4 ,
Good sir, I am simply sharing a not wildly know n fact; I have a set of JBA 2.9l headers on my 94, 4.0l rebuild, which is using 98+ OHV 4.0l heads. The reason that I used the 2.9l headers on this 4.0l is because the 98+ spec OHV 4.0l heads use the same size exhaust port size, spacing and bolt pattern.

Both the "H" and "Y" pipe variants use a ball-knuckle connection to the headers, which already permits flexibility for the installation angles. I can not say that they will fit using the new manual transmission (05MD).

I'm no rocket scientist, I just had a set of OHV 4.0l heads without headers, I noticed the similarly, checked it out and they fit.

NOTE:
2.9l headers will not work on an OHV 4.0l head from 1991-1997, only on the 98+ spec heads with the reduced size exhaust ports.

 

[85_Ranger4x4]

@85rngr4x4 ,
Good sir, I am simply sharing a not wildly know n fact; I have a set of JBA 2.9l headers on my 94, 4.0l rebuild, which is using 98+ OHV 4.0l heads. The reason that I used the 2.9l headers on this 4.0l is because the 98+ spec OHV 4.0l heads use the same size exhaust port size, spacing and bolt pattern.

Both the "H" and "Y" pipe variants use a ball-knuckle connection to the headers, which already permits flexibility for the installation angles. I can not say that they will fit using the new manual transmission (05MD).

I'm no rocket scientist, I just had a set of OHV 4.0l heads without headers, I noticed the similarly, checked it out and they fit.

NOTE:
2.9l headers will not work on an OHV 4.0l head from 1991-1997, only on the 98+ spec heads with the reduced size exhaust ports.

I was simply sharing a well known hot rodding tip, when it comes to fitment expect the unexpected.