2.5" vs 3" Exhaust Pipe for 5.3L

[TPA335]

I'm looking to get an 18" Magnaflow muffler put on with the flapper and resonator delete...basically cut off everything from the muffler back. I was at the muffler shop today and the guys there told me that the stock pipe diameter is 2.5" and since I'm simply looking for sound they suggested that I stay with 2.5" pipe. I'm reading that a lot of people here are going with 3" pipe from the muffler back. Will there be a difference between the 2 diameters (I'm not going cat back...just muffler back). I have a 3" Magnaflow muffler on order (P/N: 11259) but debating if I should cancel it and order the 2.5" muffler (P/N: 11256) instead. The shop said they can make the 3" muffler work with reducers to fit 2.5" pipe. Not sure what to do. Any suggestions would be appreciated.

 

Thanks in advance

[07Softail]

I think the stock pipe is 2 3/4 OD... go with 3"

 

RT

[nadrojcote]

Stick for mine was 3" I thought, I got a jones 3030xl 3" in 3" out, I'll have to take a look after work. I was pretty sure its 3" and the 6.2l is 3.5".

[robvas]

Stock on the 5.3 is 2.75" according to my muffler shop. Went with a 3" muffler and they made me a new tail section out of 3" pipe

 

I would not go down to 2.5"

 

On a 355hp engine like the EcoTec 5.3, 2.5" single pipe is just too small for maximum power.

[TPA335]

3" it is then. Thanks fellas...much appreciated.