The factory cat can be cut out and a new one welded into it's place by any decent welder or muffler shop. The factory cat has two 2" exhaust pipes coming into the front of it and a single 2.5" outlet coming out of the back of it. When I replaced mine, I purchased a Magnaflow Converter (99047HM - dual 2" inlets, 3" outlet, front O2 sensor port) so that I could run 3" exhaust components from the back of the cat. I also ran a 3" Dynomax UltraFlo Welded Muffler - #17233 and had a 3" tailpipe added.

 

Might also want to consider re-gearing the truck to help its acceleration. I was running 3.55 gears and installed 33" tall tires. After installing the taller tires, the truck felt like it wouldn't get out of its own way from a stoplight. I ended up swapping out the 3.55 gears and installed 4.10 gears and it really woke the truck's acceleration from a stoplight right up. Just keep in mind that if you have a 4x4 truck, the front and rear axle ratios must match. Re-gearing isn't cheap unless you know someone that can perform the swap at a reasonable price, however, its one change that makes quite a noticeable difference.

 

BClark
Do you know what a death flash is for the powertrain control modules? I would check your exhaust flow at the tail pipe before take the motor out and either replacing it or a rebuild.

 

If it had the death flash i believe it would have a sticker on the pcm that said XXXXXX was installed.

 

What you call as a death flash was a flash update to reduce the horsepower by a small percent due to the pinging or pre-detonation and the timing had to be adjust to 5 degrees BTDC. Which could have been done by sink timing or with a timing light.

 

this rebuild was already planned. The truck originally came with a 5.2 and I am swapping in a cammed 5.9l. I almost done with the rebuild. Just wondering the best route to go for tuning.

 

Make sure your controller and wire harness are interchangeable for a 5.9 engine vs a 5.2. I would also replace the cats, unless you are going without cats.

 

Yea the computer is the original 5.9l computer. Whoever did the swap originally didn't touch that. The cats ate definitely a good idea as it had 206k miles