4.0L cylinder head mod - JeepForum.com
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post #1 of 6 Old 02-25-2009, 02:58 PM Thread Starter
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4.0L cylinder head mod

im going to have my cylinder head off of my 4.0L, no reason to list why cause that not the point of this thread. does anyone have suggestions for performance mods to do to the cylinder head while its off?
its kind of hard to search for because all you end up getting is thread of people putting 4.0 heads on 4.2's

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post #2 of 6 Old 02-25-2009, 04:24 PM
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You could port and polish it. Just Google up port and polish a cylinder head. It is a marginal improvement in some heads. for other heads it is a great improvement. The 4.0 head already flows decent but there is always room for improvement.

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post #3 of 6 Old 02-25-2009, 05:49 PM
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Ya a gasket match, polish and clean up the bowls. Maby get some oversize valves and roller rockers if money is not a big thing.


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post #4 of 6 Old 02-25-2009, 05:57 PM
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on the 4.0 your not going to gain anything by port and polish cause your power is being used at low revs. acutally you can make power worse on engines like this with a port and polish. Roller rockers and other such things can help.

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post #5 of 6 Old 02-25-2009, 06:06 PM
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Get rid of it and buy this:


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Originally Posted by wjjeep19 View Post
It is what Jeeples has *PARTIALLY* stated.
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post #6 of 6 Old 02-25-2009, 06:45 PM Thread Starter
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lol at that point i would just get a later model v8 to throw in. it looks like VERY mild porting and a polish is what ill do.
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