y pipe question

[RyanDamo]

Hello everyone,

I purchased a 1986 6.9 2wd flatbed dually a month ago with the exhaust rotted out. I Got a full 3.5 inch exhaust off of a 95 powerstroke van from the junkyard and im almost done but i ran into a little snag . I thought the factory y pipe turned into 2.5 inchs after the 2 pipes from the manifolds join, but for some reason on my truck it stays 2.25. my question is if i upgrade to a y pipe off of like a 93 will it fit and will it be 2.5 inches? Im asking because mine is slightly rusy and i might as well replace it while im in there. Rockauto has a y pipe for an 86 listed for 93 dollars while the y pipe for a 93 is only 53 dollars. Can anyone shed some light for me on what to do. I really dont want to dish out a lot to have a y pipe custom made.

Thanks!

 

[Agnem]

Factory Motorcraft Y pipes were all 2.5". Most of the knock-off's... Walker, AP, et al used 2.25". That's how you save money.

 

[tractorman86]

Hell if you weren't so far away I'd sell you one, ive got two extras

 

[RyanDamo]

i dont get the logic behind anyone thinking 2.25 inches is enough for a v8 engine. is there any difference in the y pipe that would be used on a 93 7.3 idi n/a with a 86 6.9? im trying ot figure out why rock auto is charging
$93 for the 86 y pipe and $55 for the 93 y pipe

 

[plywood]

Rockauto sells one from Walker and one from Dynomax which is made by Walker.

For my 85 the Dynomax is 2 1/4s into a 3 inch. From what I can tell the exhaust manifolds are the same for the IDIs so the difference in years must be where the hangers are welded on, and possibly the bends around the tranny, crossmembers and whatnot. I noticed other years were only 2 1/4s into 2 1/2, so I wondered if other years could use the 3 inch. I have pictures on my same user on tds.

Videos below, probably have to turn it up for it to sound good.

 

[RyanDamo]

o wow it goes into 3 inch? i might have to look at that one then since i will be doing a little towing here and there. Sounds good in the video

 

[Agnem]

I seem to remember thinking that Autojet was the best aftermarket Y pipe maker. I hope they still offer one.