replacing cracked 0331 xj head with older....any issues?

redneckjeep87

redneckjeep87

Landscaper Extroidanaire
Joined
Oct 10, 2007
Location
Woodleaf, NC
Been doing some reading on swapping in an older xj head in place of the cracked 0331 2000/2001 pos. Does anyone on here have any ideas as to anything that would pose an issue with the swap? I know that the older heads do not have the mounting bosses for the coil rail but that wont pose a problem. I have seen where people say you have to run aftermarket header etc due to the exhaust ports being larger....but is it really that much of a difference? I have found a 7120( i think thats the number) out of a 91 that i would like to use due to price, location, and having the largest exhaust ports of the thres different heads.

I can read all day on other forums but i trust info on here much much more. So what say ye nc4x4
 
Noone done the swap to get rid of that pos 0331 head? There is also a couple companies that sell the 0331 heads aftermarket that have beefed up casting....but i would prefer not to be in the 700 range
 
First hand experience doing this...

It will bolt right up without issue. But there are a few little things to consider:
The 7120 will have a temp sensor on the driver's rear that you need to plug or keep the temp sender in. Also, the exhaust ports are a little different but their mounting holes and spacing is the same. You can for a fact bolt up the newer style manifolds on the older head. You may sacrifice a little power due to inefficiency, but not enough to matter. You know about the coil pack bosses, so no need to mention that. Lastly, the 0331 will have smaller cylinder head dowels than the 7120. Just leave them out and bolt it down.
Back when I was buying and flipping Jeeps more often, I would grab whatever random head I had laying around and use it. My best bud has put about 30k miles on a TJ that was running a 0331'ed 4.0 that I swapped a 7120 onto the short block.
 
I picked up a 01+ head from a WJ with "tupy" cast in it. It's a stronger casting. Took it to machine shop and had it cleaned, checked, and valved.

Or just get a reman head from auto zone for a 01+ wj.
 
I
userbmx1315 said:
I picked up a 01+ head from a WJ with "tupy" cast in it. It's a stronger casting. Took it to machine shop and had it cleaned, checked, and valved.

Or just get a reman head from auto zone for a 01+ wj.
Click to expand...

I knew about the tupy heads but didnt even think about getting anything reman from a parts house. On the tupy heads does it read /0331 tupy" or does it just read "tupy". I have a manager buddy of mine at oreillys that is going to look up cost when he goes to work tomorrow. I would almost do that than have to go find a head, pull the head, take head to machine shop, etc etc. I am self employed and dont have the time to do all that runnin around. Plus i live 30 min from the nearest shop. Do i need to get a 03 and up or just 01 and up?
 
Jody Treadway said:
First hand experience doing this...

It will bolt right up without issue. But there are a few little things to consider:
The 7120 will have a temp sensor on the driver's rear that you need to plug or keep the temp sender in. Also, the exhaust ports are a little different but their mounting holes and spacing is the same. You can for a fact bolt up the newer style manifolds on the older head. You may sacrifice a little power due to inefficiency, but not enough to matter. You know about the coil pack bosses, so no need to mention that. Lastly, the 0331 will have smaller cylinder head dowels than the 7120. Just leave them out and bolt it down.
Back when I was buying and flipping Jeeps more often, I would grab whatever random head I had laying around and use it. My best bud has put about 30k miles on a TJ that was running a 0331'ed 4.0 that I swapped a 7120 onto the short block.
Click to expand...

What did yall do for exhaust on said tj? How much did it really effect porformance/driveability/milage with it being ineffecient due to tbe steel wall the exhaust has to hit?
 
redneckjeep87 said:
What did yall do for exhaust on said tj? How much did it really effect porformance/driveability/milage with it being ineffecient due to tbe steel wall the exhaust has to hit?
Click to expand...

TJ had the stock 1 piece manifold on it. There was no noticeable performance loss or any driveability concerns.
I bought a 97 TJ with a blown engine. I then bought a wrecked 00 XJ, pulled the drivetrain and parted it out. The engine went in the TJ less the head, which I installed on a 00 WJ I had bought too. I then put the 97 head on the 00 XJ long block in the TJ and sold it to my best friend.
 
it read tupy between the center cylinders under the oil fill cap. can be seen with a flashlight and removing fill cap.
if you get the one from parts house make sure it has the valves. think it was under $500. i get mine from PAP and had it machined and spend just at 400 total with gasket kit.
 
10 4. Thanks for all the info. Im an hour from any pull apart. So when you factor diesel, time away from work(self employed), etc etc. The $444 complete ready to drop head isnt too terribly bad of a deal. Im still going to call a couple yards around here and see if they are reasonable. Plus my manager buddy can get the head just a little over cost. We will see how much that is when i call him later
 
im actually going to trade the g/fs jeep in on a new one. if your interested in the head and install gaskets send me a text. 704-923-1103 AJ.
she wants something more reliable and nice since we have a newborn.
 
Ive got a 98 4.0 head from a ZJ for $80 if needed. 230K on it.
 
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