Q on Header non-CA emissions 00-01

I finally have my first XJ, a 2000 Sport, 4.0/AW4. This unit has the non-California emissions package, there are two factory 3-into-1 headpipes/headers, but NO pre-cats. I have only 2 O2 sensors, one before and one after the single downstream cat.

Can I use any 97+ header, whether 6-into-1 or 3-into-1, as long as I get a custom down pipe made up? If not, why not?

If I can use a "normal" header, would a 97-99 downpipe also work, or is the 2000-01 single cat in a different position than pre-00?

I've searched around for the answer to this questions, but can't find them clearly stated...

Thanks for any help! I'm psyched to finally be an XJ owner!

If you get the shorty headers that are split then they should bolt right in. And you should be able to use any if you do get a custom down pipe.

Some of the 3rd gen dakotas were similar in the fact that some had pre-cats and some did not and the headers were the same.

Thanks metmknice! Anyone else share that interpretation? Assume it's true, I just need to find a descent shop here in the Cincinnati area to help with pipe fabrication.

Why,that exhaust is already as good as as any aftermarket set-up.

Based purely on airflow, the factory pipes MAY be as good as the best aftermarket, but in terms of other performance related features like weight and underhood heat control that's questionable. And, I'm not convinced that a true tri-Y doesn't have better scavenging overall. But, I lack any dyno numbers to back that up.

The 2000 and 2001 have a different head than the 1999 and older. You would need to find an exhaust manifold/header specifically designed for the 0331 head. The size and location of the exhaust outlets on the head were changed just enough that you can't use a 99 and older manifold unless you make some sort of adapter for it.

JBA, Banks, and Clifford make headers for the 2000 + . The Pacesetter manifolds are and have always been, junk.

Aaaaaaaaaahhhhhhhh.

Thanks Tim. That's the sort of difference I was wondering about. And, that makes a bit more sense as to why there are different headers just for those two years even for the non-CA emissions vehicles.

OK, so, another question then...

Were any 2000 XJ's made with the older cylinder head?

I'll poke around the forum to see what sort of head ID info is available.

Thanks again! eace:

The head has an ID number cast right on it. Look straight down from the oil fill cap next to the middle head bolt. 0331 is the 2000+ head, 0630 is one of the older styles. The 0331 was used on Wranglers until about 2005. SEARCH 0331 head and you will find threads about head cracks and how people swapped on the older style heads. Also search APN header they are inexpensive and fit well.