if i can find the article i can tell you exactly the deal. but i think i can summerize it. ok in mid 99(i typoed not 98) they changed the head design for better emissions. but what happened was the heads didn't flow well and had the tendencies to crack ,cannot exactly remember if it was between the 3rd and 4th exaust port or the exaust valves. the casting was weaker than the mid 99 and back heads.i think the years they listed as being the best was from 97 - mid 99. those had the best casting and flow of all the 4.0 heads ever.

If the production date on your jeep is prior to 6-99 you are fine. but if it is that close it wouldnt hurt to give the dealer a call and find out where to find the part number on the head.

I am concedering building a stroaker and i will definatl get my hands on a head from the 97-mid 99 range.if i am going to spend that kind of money by God i am going to make dang sure it will be strong.
my other option is finding a diesel and running veggie oil ,fuel prices are insane. <img src="/forums/images/graemlins/lol.gif" alt="" />

Wooo hooo! mine was manufactured 10-98, I have the better head. I would still be interested in reading the article if you can find it, just for education purposes.

Thanks

Sean

ok i just found it,and for sure it is between the third and fourth exaust port.and the heads you should have is 96-98. it is in an article in 4 wheeler magazine june 06 issue about jeep xj weak links and fixes for them.you can go to the website and get that issue.

which ones? <img src="/forums/images/graemlins/lol.gif" alt="" />

If'n you need parts ask the junk yard guy...he knows! Of course the cases are not interchangable.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

All of them, If it has no frame its as good as a daewuuuuuuu. <img src="/forums/images/graemlins/nana.gif" alt="" />