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Discussion Starter #1 (Edited)
My '94 Caprice wagon has shorty headers and an off-road X-pipe. I've been getting complaints about the exhaust smell so I am going to add cats to resolve that. After the headers on each side are short mid-pipes, before the X-pipe. I'm trying to figure out the best (easiest and cost-effective) way to add cats to the exhaust.

I'm hoping that the mid-pipes between the shorty headers and the X-pipe are stock, and that they're where the cats are supposed to go, so hopefully I can just buy catted mid-pipes, bolt them in, and be done with it.

Or should I just buy a catted X-pipe? I'd kind of prefer to avoid hacking up the existing X-pipe if possible. (Like if I ever want to go back to catless.)

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Some shorty headers allow a factory CAT pipe assembly to bolt right up. Edelbrock shorty for example have a elbow on the front of PS CAT welded in place vs stock.

You could just but some Catco CATS and take them to a muffler shop and have them weld them into your mid pipes or just make new mid pipes for the CATS if you want to keep the ones you have now for later if you decide to get rid of CATS
 

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Discussion Starter #3
Do those mid-pipes look like the factory catted mid-pipes would be a bolt-in replacement? Unfortunately, I don't have a stock exhaust handy to confirm. (Guess I should go hunting for pics on Google!)
 

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Discussion Starter #6
I got a reply from Bruce at Stan's Headers, and was quoted $345 each for the catted mid-pipes, which he says will be bolt-in. That sounds great for ease-of-install, but is a little hefty on cost. Does anyone make a catted X-pipe for the B-bodies? Hopefully something like that would be in the $400-$500 range.
 

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Discussion Starter #7

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Third (fourth?) vote for getting Catco weld-in's. Also, thanks for catting your car. My kids and future grandkids are happy about that
 

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All our kids will be driving electric cars ;)
 

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Discussion Starter #13
Are you guys suggesting weld-in cats at the mid-pipes (the little pipes before the X-pipe)? If so, any idea what the inlet/outlet sizes would be?

I'd definitely want cats that are as small and as high-flow as possible--I don't have any of the heat shielding between the exhaust and the underside of the body any more, so the less heat that's being generated, the better.
 

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Are you guys suggesting weld-in cats at the mid-pipes (the little pipes before the X-pipe)? If so, any idea what the inlet/outlet sizes would be?

I'd definitely want cats that are as small and as high-flow as possible--I don't have any of the heat shielding between the exhaust and the underside of the body any more, so the less heat that's being generated, the better.

yes before x-pipe, pipes are probably 2.5", easy job for a shop.
Not terrible/hard if you have access to a mig and can weld.
 

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Discussion Starter #15
yes before x-pipe, pipes are probably 2.5", easy job for a shop.
Not terrible/hard if you have access to a mig and can weld.
Is that 2.5" ID or OD? (I'd like to measure before ordering cats, just to make sure I get the right ones.)
 

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Is that 2.5" ID or OD? (I'd like to measure before ordering cats, just to make sure I get the right ones.)
Generally, exhaust pipes are OD. Just make a cardboard "U" and measure it if in doubt.
Before ordering if you're going to have a shop do it talk to them first. Local shop here was able to sell me a magnaflow CAT much cheaper than online pricing.
 

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You can always make aluminum heat shields that strap onto the pipe or cat itself, or some heat shield wrap on a piece of aluminum, and strap it to the top of the cat.
 

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Discussion Starter #18
Actually the Magnaflow universal cats have integrated heat shields, so that’s helpful!
 

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yes the magnaflo have heat shields on one side. What I have. I bought the 2.5" and had them welded it

IDK if other brands CATS have heat shields, assume they would.

I had to pay $200 each as mine were "OBD2/CARB" certified CATS

If you live in a non emission testing area just buy some 2.5" Catco's and have a muffler shop just weld them in. When I had mine done I switched to 2.5" pipe as my CAT back already was 2.5"
 

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Here's what I came up with for CatCo. They indicate that they're direct bolt-in, but I assume that's for the stock exhaust manifolds, not headers. A shame because these are $181.99 each.

https://www.summitracing.com/parts/cto-9403/overview/year/1994/make/chevrolet/model/impala
https://www.summitracing.com/parts/cto-9404/overview/year/1994/make/chevrolet/model/impala
No.

Those cats are direct bolt-ons for stock manifolds and shorty headers.

For those tri-y headers, you'll be cutting pipes all over the place, and they still won't fit.

Best bet.....from my standpoint.....is to get a set of universal cats and having them professionally grafted in, replacing the mid-pipes or into the X-pipe before the pipes merge.

KW
 
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