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post #1 of (permalink) Old 02-15-2002, 09:03 AM Thread Starter
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Exhaust Question

In my '77 CJ7 I am running a 304 with headers running out the fenderwell. The exhaust then turns at a 90 under the frame and another 90 up under the skid plate and out the back. It looks like it had duel exhaust at one point but now the passenger side just turns a 90 and is connected to the other side at the second 90. I don't know much about exhaust systems but this doesn't seem too good to me.

I am in NC and don't know much about the smog rules here. But I think I need to have the Catalytic Converter. Any thought on a better design?

Mike Z

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post #2 of (permalink) Old 02-15-2002, 09:14 AM
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Re: Exhaust Question

You may want to consider having a new exhaust system plumbed.

As far as the cat goes, I'm not familiar with emissions laws in your state. You will want to check them out.

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post #3 of (permalink) Old 02-15-2002, 09:17 AM
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Re: Exhaust Question

Your '77 might not need a catalyst. In '78 the V8s had a converter, but the sixes did not, although they did require unleaded. In '79 I think they all had catalysts.

If your header outlets are aimed so that they have to be routed over the frame rails and out the fenderwell, you might be stuck. In that case your best bet would be to tuck some small mufflers up between the floor and the outside of the frame rail, and turn the exhaust down and out in front of the rear wheels. I have a couple of friends with that exhaust setup and it works pretty well, although it always seems to be in danger of getting dragged off.

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post #4 of (permalink) Old 02-15-2002, 10:59 AM
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Re: Exhaust Question

I'm from NC. The rule for our state and any other is the same when it comes to the emissions system. They follow the EPA rules or the Fed's cut off the highway funds. I don't know whether or not your Jeep would have had Cat's from the factory. Depending upon where you live in the state, some places do a better job of testing. some counties currently do sniff tests, some do not. All are supposed to do a visual check.

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post #5 of (permalink) Old 02-15-2002, 12:06 PM Thread Starter
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Re: Exhaust Question

Thank you all.

Any Idea how I can find out if it originally had the Converter. I guess that is the main issue.
I am in Guiford county, so I do get to do the "Sniff test" but it is pretty loose for this year and I think I could get by without the converter.

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post #6 of (permalink) Old 02-15-2002, 02:35 PM
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Re: Exhaust Question

check the sticker on the top of the radiator support it will give emissions info my 75 cj5 with the factory 304 had a cat if it says noncatlyst than you dont need the cat but if it says anything about air catlyst then you need it

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post #7 of (permalink) Old 02-16-2002, 11:50 PM
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Re: Exhaust Question

i could be wrong but i don't think you had duals from the factory. should of had a "y"pipe sorta of running from your passenger side over to the driver side where both met up then thru the cat thru the muffler and then out the back. one problem some people have with running duals out the back is exiting out between the fuel tank and passenger frame rail(shackle also).this could be why you have that configuration that you have. now it may not be all that legal but in some states if you have antique tags you don't have to get an inspection, just an idea. i had heard some places won't let you run duals(cats) if it came from the factory with one.

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