79 258 - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 02-13-2002, 08:43 PM Thread Starter
 
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79 258

I just picked up a 258, rebiult and bored for $200. II've got 170k on my 258 in my 85 CJ so I am planning on installing it pretty soon.

The only thing I see different (which I thought there were not differences) is this 258 has a metal valve cover and mine is plastic. What else is different? I would like to put a 4.0 head on, what size head bolts does this '79 258 have?
Thanks in advance

Shawn

A CJ and a TJ.
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post #2 of (permalink) Old 02-13-2002, 09:17 PM
 
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Re: 79 258

I may be mistaken but I think 80 was the only year with a metal valve cover ,If you post the block and/or the head casting numbers we can natrrow it down somewhat.Someone has the casting number list on their website ,I have it printed but would need to find it.
I cant help wit the head swap stuff .

Ray
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why does everyone ask if I am gonna paint it ?
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post #3 of (permalink) Old 02-13-2002, 09:38 PM
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Re: 79 258

the 79 258 block should be good for all
4.0 heads, but i think it's '92 and up
that you want to look for. then the
intake, the exhaust, then do we try to
adapt a carb, go to f.i.....? how ya wanna seal the jackets...?
good way to go, but not real easy....


when in doubt.........
empty the magazine.
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post #4 of (permalink) Old 02-13-2002, 09:40 PM
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Re: 79 258

I may be mistaken too, but I thought the plastic valve covers started in either '81 or '83. The prior ones, I thought were metal. The head is shaped different on the left side. The earlier engines used larger 1/2" head bolts where the later engines used 7/16", this might keep you from using a 4.0 head. There is also some minor difference in the intake and/or exhaust manifolds.


I've replaced so many parts that my old Jeep has become my new Jeep.
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post #5 of (permalink) Old 02-13-2002, 09:44 PM
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Re: 79 258

I'm almost certain the '79s had the more desirable 1/2" head bolts. Also, I think the metal valve covers were standard issue up until '81 or '82, anyways it's a real improvement over that POS plastic cover.

TEXAS1AL

84 CJ-7; 258 I6; Restored-to-Stock Condition, TR Ignition Upgrade
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post #6 of (permalink) Old 02-13-2002, 11:56 PM
 
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Re: 79 258

1979 have 1/2" head bolts ... same as a 4.0 HO




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post #7 of (permalink) Old 02-14-2002, 04:37 AM
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Re: 79 258

Cool, I was suffering from the apparently mistaken belief that the 4.0 used the 7/16" head bolts and that the holes would have to be reamed to fit the earlier 1/2" bolts.


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post #8 of (permalink) Old 02-14-2002, 06:29 AM
 
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Re: 79 258

<blockquote><font size=1>In reply to:</font><hr>

4.0 heads, but i think it's '92 and up


<hr></blockquote>

- close, '91 and up.
<blockquote><font size=1>In reply to:</font><hr>

that you want to look for. then the
intake, the exhaust, then do we try to
adapt a carb, go to f.i.....?

<hr></blockquote>

- If you want the carb setup, use the intake manifold from the 258. Either way, you'll need the exhaust manifold (preferably headers) for the 4.0 you're using. I bought a factory set off eBay for $25.
<blockquote><font size=1>In reply to:</font><hr>

how ya wanna seal the jackets...?

<hr></blockquote>

- stuff the triangular holes with foam peanuts and fill them with high-temp epoxy. Carefully sand smooth.


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