I was on another post yesterday discussing exhaust, but can't find it today. It was a nicely done van using Pacesetter headers and a custom 3" y-pipe.

I was so impressed with te fit of the headers, I ordered a set.

Now here's my question, and with some other posts I've seen, it may be more of an opinion. He used a 3inch y-pipe, into a single 3 inch exhaust. With the pacesetters having a 3" slip collector it was probably the easiest. I want to make my Y-pipe also, and am debatting (mostly with myself) whether to go 3 inch and keep it simple, or try to reduce it to 2.5" Y-pipe, into the 3" inch single.

 

Personally I would stay with the 2.5". I have some pics of a 2.5" Y-pipe I built on this thread....https://www.ford-trucks.com/forums/1034582-y-pipe.html

 

I checked it out, 73FOMO, nice work. My only concern is, that with the long tube headers into a 2.5 reducer, I won't have enough room for my y-pipe to turn nicely. With the 3" it simplifies things because there is no reducer to worry about.

I'd prefer 2.5 at the Y, but 3 is so much simpler. But if the popular oppinion is that it won't matter, then 3 it is!

 

Go with what your comfortable with. 2.5" worked nicely for me and I didn't want to go to big and lose torque. I used Mandrel pipes so that makes a diff.

 

The loss of torque, is why I'm debating. If running a 3in Y will be that counter productive, then I'll figure out how to make the 2.5 in work!

 

Some times the obvious is so close you look right past it!! I'll weld a 3in 90 to the drivers collector, then reduce it to 2.5 right after it turns. The pass. collector can go right into a reducer. Then I can run 2.5 into the Y, and 3in out.

 

That should work. I picked up my 2.5 merge collector from Summit for around $26.