I was thinking about getting headers after I get my gears put in and paid off. I was looking at the Pacesetter LT’s. My first question is what size are the stock catalytic converters? I know the collectors on the headers are 3”. I was looking at keeping my stock cats for emissions purposes, and I have heard that the stock cats are pretty high flowing already. Also, since I have an emissions test, I wanted to keep the O2 sensors connected. And I was wondering on how to do that, since I’m sure that the stock wires will probably not be long enough to reach. Any information on how to make this work would be appreciated, especially from anyone who has long tubes and the stock cats.

 

There are already about 1000 threads out there on this...do a search.

If you have emissions testing there, are you sure LT headers are even legal? If so, yes I'm pretty sure you can hook up the stock cats no problem. The cats are about 12" long, 5" diameter (is that the measurement you were looking for?). Not sure about the lengthening of O2 wires

 

What about LT headers makes them illegal in some states, Anyone know? Also anyone know if they are legal in MO?

 

LT headers themselves arent illegal in some states, but the fact that you have to either remove or relocate the stock cats that makes it illegal. Check your own states emissions laws, specifically how they test for emissions. Some states will not allow you to tamper with the stock cat at all.

traker...i'm pretty sure missouri doesnt have emissions as a state law, but check your specific county. some counties require it (i.e. st. louis county)

 

Ah, I see, Thank you. We don't do emissions here, However, the do check for stuff like holes in the exhaust and etc.. I don't know how specific they have to be, I guess just out of curiosity I will ask at an inspection garage.

 

I was looking at the diameter of the input and output pipe of the stock cat, not the physical size. The header collector is 3” and I wasn’t sure how large the input of the stock cat is. And as far as the legality issue, technically they are illegal since I would have to move the cats from their stock position, which I think that is a federal law, not a state law. But as far as emissions go, I would be using the stock cats, and I would assume that as long as there is nothing wrong with them, my truck would still pass. And as far as inspection goes, there is no inspection in CT unless you are registering a new or custom vehicle. The emissions tests are done at dealers and garages, and as long as you pass the emissions test, they don’t look at anything else.

And about using the search, I used it and couldn't quite find what I was looking for, as far as how people that added LT were able to use the stock cats and sensors.

 

emissions laws are all state by state. there are no federal emissions laws. cat in and out are both 3" to the best of my knowledge. If your state doesnt have strict emissions, you probably wont have any problems.

 

I know the actual emissions regulations themselves vary by state, but I thought the “tampering of emissions equipment” whether moving the cats, or removing anything, was a federal law, not state.

But anyway, as for the cat size, I know after the y-pipe it was a 3” exhaust, but I wasn’t sure about before, I couldn’t tell if it was the same size or if it was smaller. If it is 3”, that at least answers my first question, but is there anyone that knows how to extend the o2 sensors? Are there extensions you can buy? I know I’ve seen people with LT headers and hooked up the stock sensors. But unless I’m having a brain fart and can’t figure what to search for, I can’t find anything about how to do it.

 

No with the exception of a few guys on here, if people have LT headers they either dont have any cats at all, or have replaced the stock cats with high-flow cats. I dont know the answer to the extension question, but I'd like to know, because i'm gonna be doin the exact same thing.

 

Oh, I thought I saw some people that kept their stock cats with LT’s. Well, that could certainly put a damper on my plans. I wanted to keep the stock cats; I don’t really know how well aftermarket high-flow cats work for emissions. I don’t want to fail, and actually have them look at why, then I would have a problem.