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Need replacement head advice

Ben824

NAXJA Forum User
Location
Woodstock, GA
My cousin is looking at a 99 XJ 4.0L with a either a cracke head or blown head gasket. I can get a used head from my local pull-a-part for $37.65. He doesn't have a lot of money which is why he is looking at this Jeep because it is priced very low. What year fangs of Jeeps should I focus on to get a cylinder head from? I know to stay away from 0331 casting heads as well as Renix heads for this motor. I also know there are many different castings that offer different performance values for different years 4.0L motors. I just want to get one that will math te beat that I can. The local pull-a-part has two 98s and the rest are much older. Would 98 be close enough?
 
My cousin is looking at a 99 XJ 4.0L with a either a cracke head or blown head gasket. I can get a used head from my local pull-a-part for $37.65. He doesn't have a lot of money which is why he is looking at this Jeep because it is priced very low. What year fangs of Jeeps should I focus on to get a cylinder head from? I know to stay away from 0331 casting heads as well as Renix heads for this motor. I also know there are many different castings that offer different performance values for different years 4.0L motors. I just want to get one that will math te beat that I can. The local pull-a-part has two 98s and the rest are much older. Would 98 be close enough?

Your 1999XJ 6-242 should have the #063 head on it, which was used 1996-1999 on the XJ and 1996-1998 on the ZJ and TJ. That will be a direct swap.

An adapter plate can be fabricated to use a #7120 head (1991-1995 all 6-242) in its place with no other modifications. The plate is necessary because the size of the exhaust ports was reduced with the revision making the head the #0630.

The later #0331 head (1999-up WJ/TJ, 2000-2001XJ, 6-242) may also be used, but be sure it has the "TUPY" foundry mark on top of the head, under the valve cover. It will be cast in raised letters. This is necessary because the earlier heads (without the TUPY mark) are the ones that are "prone" to cracking - search up "#0331 Club" for information on that. The TUPY (Brazilian, I believe) head is a revised casting, and is properly durable for an iron head. As I recall, it may be used with minimal changes (your #0630 head should not have the port at the driver's side rear for the gage/IP lamp temperature sensor - if it does, the boss should still be in place on the #0331 head. Drill & Tap 1/8" NPT to accept the sensor.)
 
Your 1999XJ 6-242 should have the #063 head on it, which was used 1996-1999 on the XJ and 1996-1998 on the ZJ and TJ. That will be a direct swap.

An adapter plate can be fabricated to use a #7120 head (1991-1995 all 6-242) in its place with no other modifications. The plate is necessary because the size of the exhaust ports was reduced with the revision making the head the #0630.

The later #0331 head (1999-up WJ/TJ, 2000-2001XJ, 6-242) may also be used, but be sure it has the "TUPY" foundry mark on top of the head, under the valve cover. It will be cast in raised letters. This is necessary because the earlier heads (without the TUPY mark) are the ones that are "prone" to cracking - search up "#0331 Club" for information on that. The TUPY (Brazilian, I believe) head is a revised casting, and is properly durable for an iron head. As I recall, it may be used with minimal changes (your #0630 head should not have the port at the driver's side rear for the gage/IP lamp temperature sensor - if it does, the boss should still be in place on the #0331 head. Drill & Tap 1/8" NPT to accept the sensor.)

Wow great info! Thanks so much! Really hoping I can get my little cousin a Jeep! I was the first to get an XJ and now we have 6 including me and this one would be 7!
 
Yeah, I had five myself before that little tin dictator from the City came out (because one of my landlord's neighbours is going back and forth with him. The City halfwit looked at me funny when I said, "If I can't keep them in my driveway, then the City should have to pay for storage of my projects. They're not in anybody's way, and they're not presenting a hazzard."

Back on task - people wonder why I'm writing Swappology...
 
Ok so I looked at the head on the 99 but I cannot figure out where the markings are for the head. Where exactly are they?

The ID # should be outside the valve cover, above and between the #3 and #4 exhaust ports.

I'm not sure where the "TUPY" mark would be - I think it's under the valve cover somewhere (just not sure where.)
 
The head ID numbers is always in the same spot.

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standard.jpg
 
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