I was looking to remove the cat from my 99 F250 with the 5.4l. What kind of a power differance will this make? Has anyone here done this?

 

I have taken the cats off of my 97 with a 4.6 liter. I didnt notice any huge differences, maybe a mile or two better per gallon on the highway.

 

Leave it alone, its there for a reason. Performance-wise, its not worth the effort to remove it. Late model cats are much better flowing than the old restrictive ones.

 

The reason I pulled mine of is for restriction. Either way you look at it, if you remove the cat you will get more flow. Now the reason I wanted more flow is for sound, and it definatly helped for that! Only reason they are there in the first place is just for emissions

 

I did it, and it sounds much better. My exhaust is at least 2 times as loud as before, I love it!