Will 4" pipe fit over my stock 3.5???

[Motorboy8769]

I am buying a section of 4" pipe to delete and straight pipe do I need to have an adapter kit? Or can I slide it over the stock pipe and weld it or band clamp it?


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.

[08stroker250]

It will need to reduce down to 3.5" on one end and have the proper connection on the other end to mate with the downpipe.

[Motorboy8769]

I was planning on cutting the exhaust right before the cat and then going from there to get rid of it all just leaving it stock forward of that. But shouldn't it be slightly bigger than the stock pipe to slide over it or should I but it up against it and then weld it?? Idk if I am that good lol


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.

[08stroker250]

Slightly larger, yes. Not a 1/2" though.

[Motorboy8769]

So should I just get maybe 3 3/4 inch pipe for that then? As I am sure that small section of 4 inch pipe won't do much for performance...


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.

[03silvertj]

No, 3 and 3/4 would not "slide" over 3 and 1/2 inch exhaust pipe. Exhaust pipe is not like PVC piping.

Why wouldn't you just buy a pre-manufactured delete pipe. There is no thinking/cutting/welding involved, just plug and play. Yes, it is slightly more expensive then buying a set length of pipe, but all the calculation and fabrication is done for you.

[Motorboy8769]

Hah I just read this but I just ordered the cat and SPF delete from Vivian! As well as her tuned or SCT. No what about for the muffler any suggestions in the best way to so that


2008 F-350 CCLB all stock for now... Deleting and tuning with Vivian's looney street soon.

[03silvertj]

I think you made a good choice.

[Motorboy8769]

thanks sorry for all the typing errors i am not good with computers. lol but i think i will try to get a smaller section of pipe prob 3 3/4 inch and manipulate it over the 3.5 inch just for the muffler cause i dont think there is an easier way its welded on there isnt it?

[ckehl2]

Not that I don't believe what others are saying, I was just curious... The "sattellite"(DPF/DOC) as my wife calls it, is still sitting on my garage floor, and I have 4" pipe sections left over from my exhaust install. It'll slide over, but it's way sloppy. I would see if the local parts store sells pipe adapters to go from the stock 3-1/2" to 4". I know they stock the smaller sizes but don't know about that big. If not they may be able to order it. Or stop at a local muffler shop and see what they have or can make. Find those and it should be pretty easy, weld or clamp your choice. Check out this link...
Dynomax 41894 Dynomax Reducers and Reducing Bushings