4.2L headers vs. manifold - JeepForum.com
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post #1 of 3 Old 10-01-2001, 01:53 PM Thread Starter
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1985 CJ7 
Join Date: Oct 2001
Location: IN
Posts: 131
4.2L headers vs. manifold

Has anyone swapped the 4.2L exhaust manifold for a header? What kind of power increase if any was experienced. I have been told that there is no emissions legal header for the 4.2L but so far have not been able to confirm that. If anyone can help it is appreciated.

'85 CJ-7 - 258 bored .030 w/ mid level cam, 4.0 head, Clifford intake and header, Weber 38, TFI w/ MSD 6, Black Diamond 3" lift, Daystar 1/2" lift shackles, 33x12.5 Goodyear Duratracs with stock 3.31 gears.
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post #2 of 3 Old 10-01-2001, 09:49 PM
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1995 YJ Wrangler 
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Location: Santee, CA U.S.A.
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Can't comment on what sort of improvement to expect. But for sure Borla makes an emissions legal header for your engine.

Matt Osburn

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post #3 of 3 Old 10-02-2001, 02:03 PM
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1994 YJ Wrangler 
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Just to confirm osburn, a buddy of mine was tearing his hair out looking for an emissions-legal header for his '81 CJ. Borla was the only fabricator that had one that would pass smog. He didn't see a lot of improvement, but that's not necessarily a good example as his Jeep ran like crap anyway...
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