So I have a 97 f350 powerstroke. I am looking into getting a 5" diamond eye exhaust, single turbo back. And in mass, I know on a diesel, you dont "need" the cat. and can be passed off as not having one from factory (due to 99-03 superdutys not having one) but just incase. I want to keep mine.

So Im sure someone out here can tell me if I buy a 5" kit from Diamond Eye, that doesn't use the cat, I can later on put the cat on if necessary (due to 2 piece down pipe set up) or do I need to buy a kit that already uses the cat & get a cat delete pipe? lol I just want to make sure I can use the damn thing later on if the inspection fails...

 

Unless the Diamond eye is stainless, I would pass in the salt belt.
I also would pass on the 5". It is a waste of money and space. 4" is already tight on these trucks and the down pipe is only 3", so 5" will do nothing for you.
5" is going to be a real pain to get it in there too.

As for the cat. Good luck putting a 3" cat on a 5" exhaust.

It it was my truck, I would be putting on a Stainless 4" flo-Pro exhaust

 

Right, I figured the stainless would be necessary.. but diamond eye is a preferable choice atm due to budget restrictions.. I imagine since its a 3" dp then expands to 5" piping, why is it so difficult to get it up there if theres practically nothing but frame rail. n axle?

 

I have a cheap eBay aluminized exhaust on my work truck. Cost me 230 shipped 5 years ago. Still on the truck and still very solid. Seams of the tubing is rusting heavily now though. Probably only a winter left on it now though.

Do what you want but you'll be disappointed when you buy another exhaust when you coulda gone stainless first time and be done with it. (I've already put my second exhaust on my mothers cummins and 2nd exhaust on my other superduty.... I've saved less than zero now)
Don't put the cat on it. Its only restricting. Its not helping and will look like crap when the inspector sees reducers going up and down and other ugliness.
Do 4" and get a nice 5" tip. It will clear everything better.

 

okay... so a 4" diamond eye with no cat should be good? ive just heard that the 5" sounds much better. but hey idk from personal experience lol.

ive found a few DE stainless ones on ebay/summit round 250-300 shipped. which isnt bad right?

 

I bought my STAINLESS Flo-Pro 4" kit DELIVERED for $327
From DK diesel

I would also recommend replacing any U-bolt exhaust clamps with stainless band clamps