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Unread 07-06-2014, 09:55 AM   #1
Colt44
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1983 CJ7 
 
Join Date: Aug 2010
Location: Memphis, TN, Tennessee, USA
Posts: 483
Question about which 4.0 head to use?

I have an '83 CJ7 with the 4.0 head conversion. Long story, but I need to replace the cylinder head (with another 4.0) and I'm going to source one from the local yard.

My question is simply this: I want to get a low-mileage part, which probably means getting the latest year that's compatible with my 258 CJ block.
Can I pull any cylinder head from an I-6, say a Grand Cherokee, or is there a certain range of years and/or models that I should look for, can't/shouldn't use, etc.?

I know the 7120 is supposed to be the best casting number for this purpose; does that have to come from a 91-95 Wrangler or did it (or an equivalent) go through other years and models?

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Unread 07-06-2014, 10:33 AM   #2
carnuck
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Get a head and learn how to do valves. Power wise there is little difference what year, but '99-02 are bad juju.
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Unread 07-06-2014, 01:01 PM   #3
RenoF250
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Join Date: Sep 2011
Location: Foresthill, CA
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Quote:
Originally Posted by Colt44 View Post
I have an '83 CJ7 with the 4.0 head conversion. Long story, but I need to replace the cylinder head (with another 4.0) and I'm going to source one from the local yard.

My question is simply this: I want to get a low-mileage part, which probably means getting the latest year that's compatible with my 258 CJ block.
Can I pull any cylinder head from an I-6, say a Grand Cherokee, or is there a certain range of years and/or models that I should look for, can't/shouldn't use, etc.?

I know the 7120 is supposed to be the best casting number for this purpose; does that have to come from a 91-95 Wrangler or did it (or an equivalent) go through other years and models?
They are on Cherokees as well. My engine came from a 94 and has a 7120.
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Unread 07-06-2014, 03:15 PM   #4
gmakra
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1985 CJ7 
 
Join Date: Jun 2008
Location: Chicago area
Posts: 2,893
The 99-06 castings (0331 Head) from the factory were prone to cracking. If you find one that says TUPPY its a good head they were cast in south America also the new aftermarket Chinese castings are good.
I looked for quite a while to replace my cracked 7120 head while I found quite a few they were all cracked and at $35 a Magnaflux I just got the new 0331.
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