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recent 4.0 head

570 views 6 replies 4 participants last post by  75SV1 
#1 ·
I was wondering if the head off of a more recent 4.0 engine like maybe 97-2004 would fit the same as the ones off a 93-96 engine or if there is a difference in the head on the recent tj's a xj's. also maybe the recent ones would be more desireable for some reason maybe.

thanks a lot
 
#2 ·
Meister_jeep said:
I was wondering if the head off of a more recent 4.0 engine like maybe 97-2004 would fit the same as the ones off a 93-96 engine or if there is a difference in the head on the recent tj's a xj's. also maybe the recent ones would be more desireable for some reason maybe.

thanks a lot
They should fit, but the desireable ones are the 91-95 heads. The exhaust port is bigger.
Tom
 
#5 ·
ST33LR4T said:
is there somewhere that lists the different blocks and heads? im looking at a 4.0L i think from an 89 cherokee tomorrow and would like to know what years i should be looking at.
87-90 is the "Renix" engine, 91-04 is the HO engine. Pretty much all parts bolt up between the two categories, and many of the parts bolt up between 87-04.
 
#6 ·
ZmOz said:
87-90 is the "Renix" engine, 91-04 is the HO engine. Pretty much all parts bolt up between the two categories, and many of the parts bolt up between 87-04.
what about performance wise. i currently have a 94 4.0L in my jeep. i want to buy this 89 4.0L to make into a stroker then drop into my jeep. need as little downtime as possible.

which head flows better and are the block specs the same?
 
#7 ·
ST33LR4T said:
what about performance wise. i currently have a 94 4.0L in my jeep. i want to buy this 89 4.0L to make into a stroker then drop into my jeep. need as little downtime as possible.

which head flows better and are the block specs the same?
If I were building a stroker 4.0L, then I'd try and get an 97 or newer block. They are cast a bit sturdier, more ribs and better casting technique. Plus they have a main cap girdle. I here the 87-90 (Renix non-HO's) are a bit better than the 91-96 HO blocks, but not much. Your 94 head would be the best. 91-95 heads have bigger exhaust ports than later heads and higher ports than the 87-90 heads. So better flowing. Check out this website for stroker info:
http://www.jeep4.0performance.4mg.com/stroker.html
Plus I'd look around the net. There is a lot of info. I though about it myself. But I got an '03 complete motor with 1K miles on it. I want ot get some useage out of it first.
Tom
 
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