after market cat

joenuclear · #1 (**permalink**) 02-15-2007, 10:30 AM

Do we have a source for a larger diameter cat?

Echo · #2 (**permalink**) 02-15-2007, 01:37 PM

Most people just delete the cat. If you have to go through and inspection yearly it only takes about 15 mins to put the cat back on.

BIG DADDY FORD · #3 (**permalink**) 02-15-2007, 02:02 PM

cut off the cat i got 4" straight from the turbo back and it sounds great
I put the muffler on but didnt like the sound to beepbeepbeepbeep quiet

joenuclear · #4 (**permalink**) 02-15-2007, 03:53 PM

I'm looking for a 4" cat. Is the factory exhaust 4" on the F550?

**pipelayerjdh** · #5 (**permalink**) 02-15-2007, 05:25 PM

It should be 3 1/2"

lilredpowerstroke · #6 (**permalink**) 02-15-2007, 05:48 PM

The cat inlet and outlet is 3.5. All you have to do is cut off enough of the in and out to make it 4 inches then weld it to the new 4 inch pipe. Problem solved.

joenuclear · #7 (**permalink**) 02-16-2007, 04:55 AM

Doh! Cutting and welding 4" flanges should work. Thanx. I wonder what the I.D. on the factory cat is? Is is stainless?

It wouldn't work to weld on new flanges if the I.D. is < 4".

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