When I had my true duals done a few months back the exhaust shop said the ran all 2.5” pipe. The shop that’s installing the LT headers sent me a picture showing that the exhaust shop ran 2 1/4 not the 2.5 that they said. Do you think dual 2 1/4 will be sufficient with the American racing LT headers or should I go back and demand the previous shop to redo the work with what they said they were doing?
If they re-used the original pipes from behind the muffler to the back bumper they're 2.25". Did they charge you for a complete system from the collectors right back to the rear bumper,or just from the collectors to the mufflers.
If all you have is a bolt-on truck with a set of long tube headers and tune,you won't notice much differance by increasing the size of the pipes to 2.5",in fact you might even lose a bit of bottem end torque.Remember you only have 345 cubes feeding the exhaust,and it's only revving to maybe 6,000 depending on your tuner and where he's shutting the truck down.In most cases 2.25 pipes will match or exceed 2.5 pipes under 5,000 rpm,unless you're boosted or spraying it