2 1/2" mufflers on stock 2 1/4" pipes?
 

Hey, haven't had to ask a question for a while untill now.
I have been reading that alot of people have 2 1/2" mufflers welded onto their stock pipes. How does this work? Is the outside diameter of the 2 1/4" pipe close enough to the 2 1/2" ID of the muffler? Or do they use a reducer? Just wondering because my brother is about to purchase some mufflers for his 99GT.
I just put 2 1/4" in Flows on my stang because thats all that I thought would fit. As always, any help is appreciated.

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1997 Thunderbird 4.6L: Dynomax cat-back, MN-12 perf. offroad downtubes and Y-pipe w/ Magnaflow resonator, 80mm MAF with cone filter, B&M trans cooler, Inject-Tech chip, MAC U/D pulleys, KVR front brake upgrade. 15.2 @ 91 before exhaust & pulleys. Not bad for a 3800lb auto 4.6L

No Longer own: 91 LX 5.0L 5 spd

They use a reducer.

Have 2 1/2 inch 40 series flows on my 2000 GT.

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64 1/2 "D" code Red Mustang Coupe. 289, C4, Mallory duel point. Ported & Polished 65 heads shaved .01 with 351 valves, 11:1 comp, 1.7:1 rockers, blue wolverine lumpy cam, modified 4100 Hipo 4 barrel. GT Apperance pkg. And to many others to list

2000 Perf Red Mustang GT. 5spd. BBK Underdrive pulleys, Flotech off-road H pipe. Hurst T-Handle, 40 series Flowmasters, Steeda Tri-Ax. Ordered 4:10's.

64 1/2 red 6cyl coupe. Future resto.

anything to help me here to im in the same perdicament exhaust searching is exhausting ha ha. looking into a bassani for my o1 gt automatic

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2001 4.6 gt automatic bone stock for now

Are you guys sure the stock exhaust is 2 1\4??? I was always told that the stock exhaust was 2 1\2 in. I know the tails on the '99-up GT's get wider at the tails but I think the rest of the exhaust is 2 1/2" but I might be wrong.

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Red '97 Mustang GT
Auto
Bone Stock!
(Except for silencer)

for 96 and im sure the same for 01, exhaust was 2 1/2. i know this because i purchased 2 1/2 inch exhaust, matched it up to the old stock one, and it was exact same size.

No, the stock is 2 1/4". Almost all aftermarket uses bigger 2 1/2" pipe, which will bolt up to the stock stuff fine. I believe the newer Cobra's have 2.5", and aftermarket catbacks are 3" for them, but the GT's have 2 1/4" stock w/ 3" tips.