With a 2001 F-350 with a 7.3, what do I HAVE to have to be legal with a DOT number in Iowa? I have a cat on there now. Can I strieght pipe it, or do I have to put a cat back on? I do not need a mufler with a diesel do I?

 

the laws are more by noise deceibel levels rather than original equipment. Since you have the turbo and cats still there, you will likley be able to keep it down enough to avoid a ticket.

 

I ran without anything for 8 months Ion my older 7.3l idi that much noise allthe time gets annoying but you should be alright even if you plan on taking the cat off.

 

Ok guys, thanks for the info. *thumbs up*

 

my 2000 doesn't have a cat never did, and has a straight through 4" muffler, and is completely legal.

 

My 6.0 is straight piped with 4" SS. I did keep the kitty buy who knows for how long... I was always more of a dog guy.... I thought most of the 7.3's didn't have kitty's.

 

most of the 7.3s did have them, I think (but not 100% sure) that only Calif, and Co. emissions certified vehicles had them with the 7.3

 

You should be alright, I removed both the cat and muffler with just a straight pipe, and it wasn't bad at all from the cab, not real sure what it sounded like roarin' down the road. I now have a full 4" with a big flow thru muffler and it doesn't sound much different, maybe a little better tone.