4 Inch Exhaust Adaptation

[YachtTech82]

I'm hoping there isn't a thread out there for this already, I tried the search but didn't see what I'm looking for. I would like to adapt a 4 inch straight exhaust kit from a 94-97 powerstroke onto my 1990 7.3l idi N/A. I have seen bits and pieces on different forums about this but nothing very clear. I am ok with replacing the factory y pipe if needed. Not sure on what parts I would need to make this work. Should I order a turbo back kit or a catback kit? Is there a flange I can purchase to bolt to the factory y-pipe that expands up to 4 inch or am I looking at building a custom y-pipw the bolts to the 4 inch setup. I haven't seen any pictures or an explanation of what others have done. Thanks.

 

[IDIBOBS]

Since it’s not going to matter for performance on an NA your limited by the manifolds anyway and this is just for looks id just do it as a cat back system and get an adaptor from stock to 4” and weld it in someplace under the cab.

 

[YachtTech82]

Correct not for any type of gains other than looks and making noise(16 yr old son) we also live on a small island with a speed limit of 45 so I'm not too worried about drone. If it's too loud a muffler will be installed by dad

 

[u2slow]

I wouldn't re-vamp the y-pipe. Use a simple pipe size adapter as already suggested. 4" pipe may actually drop the raspiness somewhat.

Ubolt style clamps are my least favorite method of joining exhaust.

 

[Clb]

Ummmmm
What cat

 

[u2slow]

Ummmmm
What cat

Powerstrokes have one; so that's where his cat-back exhaust wants to bolt on. That's probably where to buck the flange off and use the 3-to-4" pipe adapter.