Looking for the best muffler for my 5.4. I've pretty much decided not to go with the whole cat-back and just stick to changing the muffler. I'm assuming my entire exhaust is 3" and all I have to do is buy a muffler with 3" in and out. I've been researching this for a while and need help/advice. Oh, and it's for a 2001 F250 4x4 - every day work truck and I have to keep the decibels down, please.

 

thewhiteford,

I'm leaning toward the Flowmaster DeltaFlow 40. Should be plunty of back pressure since I too want to just change out the muffler and not any pipe. You might want to go with a DeltaFlow 50 on yours since you want to keep the db's. down.

I wish I could hear both of them before I buy.
I've got a 2002 F-250SD 5.4 4x4.
Will Post when I do get one.

 

thewhiteford

The exhaust is 2 1/2 inch. With the right cat back you'll like it. I've got the Gibson Swept Side and love it! 3" but great towing power yet the sound is good not loud.

 

If you have a Superduty then I believe it is 3". If you measure the circumference it should be a little less than 9 1/2". 2 1/2" tubing should be 7 7/8" give or take.