It appears as though I have two cats (05 Sierra 1500 5.3 4WD), so which would be a better choice for performance? Assuming it is two cats, should I go with a true dual cat back system, or a single in, dual out? I assume with a true dual system, I'll also have to have a crossover pipe of some sort to equalize exhaust pressure.

Also, what are headers and how do they work?

 

Just pop the hood son Read this article... HowStuffWorks "How do exhaust headers work to improve engine performance?"... Pretty easy stuff to understand.

As far as your exhaust setup goes can you remove all your cats? If you can you can do a Y pipe setup with dual out tail pipes after the muffler of your choice. Otherwise a catback is your only bet for emission reason. I dont think true duals are necessary unless you start modding your engine to the point where you need to let the truck breathe

 

Thanks for the link, it was helpful. My intent ultimately is to put a 6" lift and 35" tires on the truck, and I plan to increase the power so the little 5.3 isn't struggling to roll them down the interstate or down the trail during deer season. I'm looking eventually at adding an intake, exhaust, an MP1900 supercharger, and a chip or programmer, although I haven't done much research yet on the computer side of things.

I have to be able to pass inspection, so I have to keep the cats, which brings me to another question. My last truck was a straight-pipe Ford diesel, so cats and even mufflers seem awfully restrictive. Will the cats block enough exhaust gas to negate headers or dual pipes, or will I still get decent gains in exhaust efficiency even with cats?

Edit-Another question. If I get headers, in order to stay emissions legal, will I still use the stock cats, or do I just buy two universal fit cats to install shortly after the collector?

 

single 3" will work fine for you. gear the truck properly and that 5.3 will have no problem at all pulling 35" tires. my brother in laws 5.3 pulled 53" tires just fine

 

At what cost of fuel economy? MPG isn't my only priority, if it was, I'd have a prius or Ranger, but I'd rather not dip into single digits driving around town. And is it true that torque will suffer with the reduced backpressure of a true dual system?

I know many put in exhaust kits for a better sound, but my desire is strictly to improve performance as much as possible while staying emissions legal. Understanding that the faster the exhaust gas gets out of the way, the more efficiently the engine will run is easy, but I am not smart on how the O2 sensors and backpressure affects performance.

I'm thinking of researching a set of long tube headers flowing into universal fit cats, then through their own pipe on each side, but will I need to add a crossover pipe to equalize backpressure, or will the headers do that for me?

 

35s are going to kill gas mileage. no way around that.

 

This^

Are you looking for a deep tone exhaust?

 

I don't really much care about how the exhaust sounds. Right or wrong, I see people who get exhaust systems for the sound the same way I see people who buy the stick-on hood scoops. I'm looking for improved performance regardless of how it sounds. If it has a low rumble with light engine load and a loud roar when I get on the throttle, so be it. But I want power anywhere I can find it while still maintaining some semblance of driveability and reliability.

My brother-in-law has an '05 Silverado ECSB with a 6" lift and 35" Nittos with an aftermarket steel bull bumper and he's getting 17 or 18 MPG on the highway when I drove it according to the driving coach on his tuner (Not sure how accurate those are) and all he has in terms of performance is an aftermarket intake and a Bully Dog GT tuner. If I get an MP1900, exhaust, and tuner/programmer, among other little things, I see no reason why I can't stay at or slightly improve my MPG with bigger meats and a lift.