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2000-older head on a 2000-newer engine?

JONNYD

NAXJA Forum User
-Accidetally posted this in modified, tech....hopefully I get a better response here!


I picked up a couple of '92 heads in great shape for a port/polish project for my XJ. Problem is, I have a 2001 (different intake, exhaust, ignition, etc). I know the 96-98 heads have a different port for the coolant temp gauge sending unit, but I dont know enough about the later model's interchangability. The '92-'95 heads are touted as the best, so I think I am on the right track, I just want to know the problems I will face when swapping onto a 2001 engine. Has anybody done this? I will port match intake/exhaust (cast manifolds!) , and probably re-cam as well. Any suggestions? Am I better off starting with a 2000-newer head?
 
Yeah, I'm welding two engines together, pretty cool huh? I got a deal on two, so I can afford to mess up one of them while porting (learn where the thin spots are, work on my finish) before I do one for real. I am planning to do a few more for some guys at my work with jeeps. Thanks.
 
don't mean to hijack the thread, but why are '92-'95 heads considered best? I didn't know they changed other than pre/post 97, and then I thought it was just the intake that changed? any info is appreciated (i'm an engine noob)
 
The '91-'95 7120 head and the '96-'98 0630 head are the best for performance. The '99+ 0331 head ('00+ on TJ/XJ) has smaller exhaust ports and is also more crack-prone when overheated.
There's no problem bolting a '92 head onto a '01 block. My stroker has a '92 head on a '00 block and it was easy. The newer blocks have dowel location pins for the head but these do not interfere with the earlier heads.
 
Thanks Doc,
I saw you used a '92 head on your stroker and I assumed a '96-newer block but I dont remember seeing what year...now I know. Thanks all, wish me luck.

Anybody find roller rockers that work on a 4.0 other than the yella terra ones? I can buy kick ass rockers for a V8 alot cheaper than $460!!!! I assume they are so expensive because they are from Australia, but come on, hasnt anybody made one to compete?

-Jon
 
No, they're expensive because they are the only bolt on no spacer or drilling/tapping ones out there and they can get the $460 they are asking for them.
 
Can you retro fit any from a different company or are they pretty much the only one's that make these things? There are only a few million 4.0L's out there, I'm sure if a company would market some for $275, they would sell enough to cover the profit margin. I would pay $275, I will not pay $465. I'm sure I'm not the only one out there with a 4.0L and that mentality. Just my $.02. Come on doc, give me some alternatives.
 
Unfortunately there aren't any significantly cheaper alternatives to the $440 Yella Terras. I've given the lowdown on all of the available RR's for the 4.0 here:

http://www.jeep4.0performance.4mg.com/valvetrain.html

Whichever you choose, you're gonna end up spending $400 or more anyway. Forget about retrofitting RR's from other models. The only ones that could be suitable are from a Chevy I6 or a Ford 300 I6 and they're just as expensive.
Unless you're gonna build a high $ race motor, I'd say forget about RR's. Bang for buck, they're just not worth it.
 
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