Well third times a charm. I never really liked the 3" PS y-pipe. I always thought it was too much for my little 5.3. Well..... I think I was right. I went with a true dual exhaust. Starting with my PS headers into 2.5 pipes. Each pipe is going to its own high flow cat before entering a magnaflow x-pipe. Then each pipe has its own magnaflow muffler, straight through design.... up over the axles and both pipes dump up high so you cant see pipes when truck is on the ground.
The throttle response is sooo much better. It pulls much better from a roll now too. Amazing how much difference an exhaust will make.

 

huh thats pretty cool. now go get it dynoed again and see if you gained torque

 

actually you have it all backwards.
2.5" true duals is > 3" y pipe

 

thats the next plan to get proof on dyno. But no mistaken the difference Im feeling. Its not a small difference.... its night and day

My old exhaust was 3" PS y-pipe into single 2.5 pipe... into single in 19" magnaflow dual out. This was much louder and less responsive. I originally didnt have any cats, then added one and seemed like motor liked added back pressure

 

The OBX system has a 2.5" y pipe versus 3" on the pacesetter y. I noticed no difference down low with the 6.0. But I do believe the 3" is too much for a stockish 5.3. The pacesetter should make a little more power up top.

 

I dont think a 3" Y pipe is too much for a 5.3L. Now 3" duals ya, probably overkill. 2.5" duals have always worked well though; good to hear the results.

 

Your original system sounds pretty mis-matched, big 3" pipes choking down into a single 2.5" pipe, scavenging must have been horrible. I also agree that a 3" y-pipe is a little excessive for a mild 5.3....2.5's into a single 3" merge sounds about right to me.

 

i had WAY WAY WAY better results with 2.5" true duals, mandrel bent, x pipe, dual bullets than i did with a big y pipe... AND it sounded much better with the duals... i'll be sticking to a y pipe setup on my new truck though, trying to stay as "stock" style as i can...

 

Is the stock catback pipe hurting my performance with the pacesetter y pipe? I think the stock pipe is 2.75".

 

Since you have a 6.0 I'm sure it's not helping any...not sure if you'd feel the difference between the 2.75 and 3.0 pipe in your butt-o-meter though