I got to test fit the Flowmaster Y-pipe I bought listed for '85-'95 F150 trucks with a 5.0L onto my Hedman street headers listed for '85-'96 F150 trucks with a 5.0L, they somewhat fit but the problem is the pipes are just a smidge too close together. I didn't measure the offset as I wasn't thinking at the time, but I would guestimate 1/2" off is what they are. Is there any way to spread this pipe out from each other to get a proper fit? Or is it going to be one of those chop it in the middle and then add filler pipe?

I prefer not to cut if I don't have to, I was thinking of maybe making some kind of press to fit between the two pipes to push them away from each other and use a little heat in the pipe to get the spread. I also thought about just loosely bolting one side up and then starting the bolts on the other side and then working back and forth letting the headers push the Y-pipe out into shape. Doing this however I am afraid of possible damage to the cone either on the Y-pipe or on the header themselves.

If anyone has any ideas, I am all ears as this is new to me.

 

How much is "a smidge" in imperial measurements? Like an eighth of an inch? . . . or an inch? . . . or . . . ?

Maybe a few pictures would help?

 

Ill try to get some pictures this weekend, but it looks like when one flange is lined up the other socket is off about 1/2".

I was told on another forum to get some 2" iron pipe and place in each collector and use the pipes to manually tweak it out till it lines up. I might just end up taking it to an exhaust shop and see if they could tweak it for me instead since I dont want to mess up the sealing cone.

 

If you heat the side of a pipe and let it cool it will curve in that direction. In other words, the part you heat will shrink when cool. SO the side of the pipe you heat will get shorter and "bend" that direction. Don't concentrate heat in a spot, move in about a 2"-ish patch. 1/4" per side adjustment, depending on how far away from the end you can make the "bend", is definitely doable. Keep in mind it's going to go the wrong way when it is hot, metal expands when hot, but when it cools, the molecules get a little more comfy with each other and pack in tighter, making it shorter.

 

Exhaust pipes are thin-gauge mild steel. it'll bend. I've bent many of Y- and H-pipes by hand.

Just pull or push (or bolt one side in and ratchet-strap the other leg into place). Either way, you will want to pull it farther, so when the strap is released it will spring back to a lesser bend - just so you don't have a side-load on the flanges. Leaving the side-load will stress the manifold, and may crack it over time...