Head Swap

[SeanM]

Anyone know of any heads that would add some horsies/torque by replacing the 4.0L OHVs heads with them? (it has heads don't it?) Let me know if you know of any...

Sean
____________________________________________
1995 XLT 4.0L V6 OHV automatic 4dr 4wd
- Superchip Module
- K&N FIPK (Fuel Injection Performance Kit)
- Flowmaster 40 series Exhaust
- Bosch Platinum +4 Spark Plugs
- Splitfire Ignition Wires

 

[Texan01]

Supposedly you can swap the 90-94 4.0 heads on there to raise the compression and give you about 10% boost in HP. They are a direct bolt in.

Now in practice it may ping like a mother on 87.

 

[DocVijay]

Try Vanir.

Web Site:

http://www.vanirtech.com/

 

[SteveVB]

Check this rebuilder article out. The 98tm heads may give you what your looking for. I doubt you would get 10% increase from them, but a 3-5% may be doable. I would do a head swap with a cam upgrade IMO, youre removing and re[placing lots of the same stuff, and you can do the head work you need to work with the cam.

Dead Link Removed

Check the site for old threads on cams and the head swaps you will find plenty.

Good Luck

 

[Guy Groves]

The 98 heads will increase the compression by about 1 point. The cam you use will depend upon upon where you want the power curve / torque. Vanir is a good place to get information. e-mail them with questions. They will answer, but they are a little slow at times (especially now since race season is on).

If you are going through the trouble I would go ahead and get the heads ported. They should be bowl ported and some mild cleanup on the ports.

I never did the measurments, but the 98 heads have considerably smaller exhaust ports compared to the early castings. I would tend to go towards a port match between the heads and headers. If you are using the stock exhaust manifold I wouldn't bother.

Next you will have to consider the exhaust and intake systems. A larger throttle body, headers and CAT back would help. A larger MAF might help a little,but the throttle body will get you more response.

 

[SeanM]

Assuming that I have the stock exhaust manifold and have no intention of replacing it, are the heads still a good idea? If so, assuming that I have the stock MAS, a Flowmaster 40 series catback, and a stock throttle body, is it STILL a good idea? Basically, will I run into any problems with air circulation or anything of the sort? Basically, what are the pluses and minues?? Also, what sort of increase in hp/torque am I lookin at??

Sean
____________________________________
1995 XLT 4.0L V6 OHV automatic 4dr 4wd
- Superchip Module
- K&N FIPK (Fuel Injection Performance Kit)
- Flowmaster 40 series Exhaust
- Bosch Platinum +4 Spark Plugs
- Splitfire Ignition Wires

 

[SteveVB]

Sean,

Heads wont give you much increase by themselves- they will work better when other mods like exhaust, a new cam are installed.

I would spend the money on headers, TB, MAF, Chip, before pulling the engine apart.

The heads will work with the stock manifolds.

6-800 for heads would be better spent on headers, or put towards a S/C kit. Regearing may be a better option also depending on what your looking for.

The heads would get you maybe 5-8 hp. Any o0f the above mods may get you similar results with less $$ and time invested.

Good Luck

 

[Guy Groves]

Sean,

Steve is right. I would also do some of the "breathing" mods before I did the engine work. If you modify the engine and don't take care of the intake and exhaust you probably won't notice any difference at all. The stock components you have will work fine even if you do the head modifications,just don't expect any real improvement.

From you description you already have a K&N and flowmaster CAT back. This is a good start. You will want to check with Superchip, as I would expect that you will need to have the chip re-programmed when adding any new mods.

As Steve said, I would go for headers and a larger throttle body. A larger MAF I think is optional. It will give you better throttle response, but not more HP.

The headers and throttle body will give the best noticable performance boost, and you won't have to pull the engine.

After that you can consider doing engine work, and you will already have better air flow to take advantage of any head work you do.

Good luck

 

[DocVijay]

I'll have to agree agree.

The money is better spent on things like a chip, intake, throttle body, MAF, headers, etc...

It would probably be better to replace the headers before polishing/porting the heads. You can do it now, but you won't get much in the way of results.You'll only be disappointed for the money you spent. Do the other stuff first.

 

[SeanM]

Ok, you guys have convinced me to hold off on the heads. But now you have also forced me into a predicament. Which do I do?? I currently have a Superchip Module, K&N FIPK, Flowmaster 40 series catback, Bosch Platinum 4+ plugs, and Splitfire ignition wires. Which of these three should I modify in order to get the best possible gains in hp/torque?

1. Headers
2. Throttle Body
3. Mass Air Flow Sensor (MAS)

Let me know....

Sean

____________________________________
1995 XLT 4.0L V6 OHV automatic 4dr 4wd
- Superchip Module
- K&N FIPK (Fuel Injection Performance Kit)
- Flowmaster 40 series Exhaust
- Bosch Platinum +4 Spark Plugs
- Splitfire Ignition Wires

 

[DocVijay]

The headers would probably give you the most hp/torque. The throttle body will give great results in the way it feels, but will only give a few hp.

My opinion, do the throttle body, then the headers, finally the MAF.

Finally after all that, port/polish it.

 

[SteveVB]

headers

Sean I would do them in the order you listed them, the headers will give the best bang for buck so I would do them first.

Headers, then the TB, then a MAF. The headers will give you the power, the TB and the MAF drivabliity. I would even suggest you skip the tb and the maf after the headers and go for a cam, and port & polish heads with the cam install, the dollars may be better spent. After a cam install the TB and the MAF will add plenty of value since the engine airflow/rpm range has been increased and may actually need the larger TB, and MAF.

Just some thoughts.

 

[Guy Groves]

In this order:

1) Headers:
You will get the most noticable performance gain here in both HP & torque. Lay out the bucks and get good JBA headers ( ~$450 last time I looked)

2) Throttle Body:
Note: The throttle body won't add much at this time except for drivability. It will be more valuable after doing some of the head work. Now or later does not matter. Besides, you won't notice the TB for performance gains until you run at higher RPM (>3500) when you need more air. (BBK 66mm TB ~$190)

3) Head work:
TM98 heads, bowl port, mild runner porting, some exhaust port matching, and polishing. (I am not a real believer in polishing the combustion chamber unless you plan on doing it yourself. It's a lot of labor cost that really won't give this engine any added performance.)
New heads - TM98 ~$600 (pair)
Porting Labor - Mild port job ~$300 - $450
New gasket kit- $80 (must have, head rebuild gasket kit)
New head bolts- $35 (must have, DO NOT use old bolts)

Note:
A) There is an aftermarket valve train kit that is a bit better than the stock from Delta Camshaft OEM replacement with hardened push rod cup. Phone: 1800 562 5500
B) If you go for a new cam you will also need to replace the valve push rods, and springs. You should not need to replace the roller lifters.


4) MSD or Jacobs Off Road ignition system.
Better combustion (multi spark) at low RPM and on inclines where you need it wheelin (~$350).


Depending upon your priorities....
Before working on the engine you might consider some drive train / suspension modifications aimed at increasing your off-road capability. Body / suspension lift, larger tires, lower gears might be next before you tear into the engine.


Yes, there is always something else to consider.
Be content to make your mods one at a time as your budget allows.