Hey guys and gals, I have an 06 Silverado 1500 5.3 4x4. Had a 5.3 in it. Pulled it out and put a lq9 with a 212/218 high lift can. Still running stock 5.3 exhaust, could this be the reason my truck does seem a little poochy down low? It does have 3.42 gearing but my 5.3 seemed as torquey 2000rpm and lower.

I was debating pulling off stock cat back setup and see if it gains some snort

 

made over 500 rwhp with a stock 53 catback, had headers and no cats prior

not saying its ideal but giving you idea

 

Alright, I was hoping I would hear that the motor needs to breathe more lol.

It has a stock tune out of a 2006 silverado ss i believe, My buddy just uploaded a base tune so the truck would run.

 

needs to be tuned for the cam

 

Ya, it needs tuned.

 

Lots of factors at work with this build. Really really needs a proper tune to wake it up. The exhaust is not ideal by any means, but it's worst in the higher RPM ranges. All things considered you really should get a proper tune and some long tube headers. You can get stainless LTs for about $300. Also a new straight thru muffler would be great. A big body magnaflow would be a good idea. You will gain a lot of power from doing so especially up top.