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...

 

I will keep that in mind, that might be an option to go. I been busy with other things and one of the suggestions I had else where was to get some cheap steel pipe that fits fairly snug in the exhaust tubing to not deform the cone and use it for leverage to push the two pipes outwards by hand tweaking a little at a time. Only thing I could find cheap how ever was only 2 foot sections and they were nearly $50 a piece.

Little different than that, the Y-pipe I have is a Flowmaster converter/Y pipe assembly for a 84 - 96 302 F150, its not thin-gauge mild steel, its mandrel bent stainless steel, I couldnt find a specific on what type stainless steel nor what gauge, not even holley`s website states that. Summit and Jegs dont state it either and Summit and Jegs give different years it fit than Holley. I dont know if I could pull the pipes out by hand without using some kind of tubing stuffed inside the cone flange itself for more leverage. I also dont have cast iron manifolds I have hedman street headers so I dont know if I want to bolt one side up and then ratchet strap the other side and pull it apart. Last thing I need is to damage the headers and void the warranty on my jet-hot ceramic coating on them.

Originally I was thinking of making a tool something like the manifold spreaders for GM cast iron manifolds basically two cups that fit on each end and a adjustment sleeve that as you turn it pushes the two cups out. Problem is will require quite a bit of all thread to cover such a gap and not sure how strong it would be plus I wouldnt want to deform the tubing.

Im going to try and finish going through the last of what I brought home from work and toss what I dont want and I am going to start messing with this again as now I have all the time in the world to finish this up and get the engine in my truck. My last resort how ever is going to be chopping the Y pipe under the oil pan in half putting the two pipes to the collectors then tacking in a splice. I dont want to do this as it negates the purpose of buying the stainless steel Y pipe vs hacking on the rusty original Y pipe, but if that is my only choice then I guess thats my only choice. I do how ever want to get it fitting while the engine is still on the stand so I dont have to fight it under the truck after I drop the engine in.

I also need to mark where I plan on putting the O2 sensor for my Sniper and then drill it and take it in and have an exhaust shop weld in a bung for me. I would attempt it but this is stainless steel and I dont have anything for that and last time I messed with aluminized steel to plain steel the welds didnt come out too nice.



I will try to bolt up the Y pipe on the passenger side loosely to and take photos and measurements to show how far off everything is. I wished I could have done this sooner, but the last 4 weeks I been dealing with clearing out a bunch of stuff from work since the shop let me go after nearly eleven years of employment. So bright side I have time to do my engine but downside is I still got some stuff to go through as well as some engine parts I need to take to this engine builder I know like my F4B intake manifold, see if I can unload if for a few hundred. I also contacted Holley to see if this might be a defect and see what they say before I go actually trying to tweak anything. Below is what I have which to me rules out a mismatch of parts causing my fitment issues.

Block : F1SE 5.0L manufactured 1994
Heads : #1399 AFR Renegade 165cc, Stock location/height intake/exhaust ports
Headers : #89470 Hedman Street Headers, OE collector flange 1986 - 1994 F150/Bronco w/5.0L
Y-pipe : #2020057 Flowmaster, 1984 - 1996 F150/250 w/5.0L

This is going in my '82 F150, I will cross that bridge if there is a fitment issue there which I dont believe there will be considering '80 - '86 F150 trucks are the same and the headers and Y pipe is listed as fitting this generation. Currently my issue is getting the flange to fit without side loading my headers. For a good seal I will be doing like I heard from an old timer I think he said axle grease I know it was grease I just cant recall exactly what type but he said a thin layer of grease on the socket side of the flange will create a seal as it will turn to a shellac with exhaust heat and it will remain soft and seal as well as allowing for some movement which would fail if I were to use something like copper RTV like I had some tell me to use which I know you dont use.

Hopefully I can get this resolved as I am anxious to see how my new engine runs and get some videos to post on here and the bullnose forum by the end of this year.

 

As promised here are the two photos of how far off my Y pipe is from fitting. The passengerside collector is loosely bolted up and the ball and socket flange is connected. This is how far off the driver side is, if I center the pipe and off set it, it doesn't need to move much but this right here is roughly half an inch it needs to shift to line up center to center. I could in theory chop the pipe that crosses under the oil pan and bolt both sides up then put a splice in but we are talking about such a small splice it honestly isn't worth the time or money of doing it, but in looking at it closely when I was taking these photos it looks like if the cone was welded in with a slight angle it might would line up.

I could also put the bolts in and tighten it up but forcing it is how these collectors leak by deforming the sealing surface, so I don't want to do that either.

Between the options I know about is using two long pipes stuffed inside the Y pipe and use it for leverage to push them apart or cutting and welding in a splice to widen it, the cost comes out about the same in the end. I thought about using ratchet straps and put the Y pipe on the posts for my carport but I don't know how strong those square beam posts are. I know I don't want to bolt one side up and ratchet strap the other side to the frame, I don't want to put that kind of stress on steel tubing headers especially considering they bolt to aluminum heads.

 

I had been installing a 5.0L Mustang catted H-pipe that needed to be tweaked to fit the factory headers. IIRC it was too narrow by about a half-inch as well. Off the car, I just stood on one pipe and pulled the other to spread them to the proper spacing. ...now of course, those headpipe flanges were almost 3-1/2 feet from the H-section.

 

I thought of trying that, standing on one pipe and pulling on the other. These are so tightly made on this Y pipe its quite stout but I also really didn't put a whole lot of effort into it.

Photo of the whole Y-pipe showing just how compact it is, also the two pipes are actually one pipe they cut it partially and then bent it to avoid having to weld V of the two pipes merging in the Y collector. That also stiffens this pipe up considerably.



I do still have to take this pipe in to have a O2 bung welded in as the one in the cross pipe isnt adequate for my Sniper 4150 Stealth EFI system. I might be able to check around and see if one of them could possibly tweak it for me but if they did it would probably put a crease in it somewhere cause only two shops under the same name has the mandrel benders and they quoted me $1,000 to build a tail pipe for my truck as I wanted a 2 1/2" mandrel bent stainless steel tail pipe to go with my mandrel bent stainless Y pipe.

 

$1000 for a stainless tailpipe? They're outta their mind!!!

I have stainless 3" mandrel-bent tailpipes on my 7.5L trucks.

My previous truck with 3" tailpipe used something like this... ~$100 https://www.summitracing.com/parts/wlk-54745

For my current 7.5L truck, I used a Dynomax 55082, at ~$130 which supposedly fits a Dodge, but I can weld my own hangers where they need be. The difference with this Dodge pipe is the exhaust exits at a 45° angle instead of straight to the side like the stock Ford pipe... BUT it DOES have a polished stainless tip! https://www.summitracing.com/parts/wlk-55082

Not sure what 2-1/2" pipes will fit, but don't be afraid to look!

 

That looks like a "put some long bolts in it and crank it down" type of firment. If that doesn't float your boat then do you have a floor jack or bottle jack handy?

How is it not adequate?

 

I have in the past left the bolts loose and use a ratchet strap to get the headers and y pipe to fit properly.

What is the part # for that flowmaster y pipe?

I'm getting ready to replace mine

Thanks

 

Their claim is that the stainless pipe they have to use for mandrel bending is way more expensive to prevent collapse, they dont use that stainless pipe for a press bend process. I couldnt say but there really isnt anyone local to me but them that I found that could do mandrel bent stainless pipe.

Theres not enough flow on the cross pipe between the two tubes is what I understand. The fitting in the header is too close to the collector and after getting my truck up in the driveway and starting to strip the engine down for removal I dont think I could even use an O2 sensor in the header pipe and have it easy to access. The cross pipe would be the easiest to access for sensor replacement with mounting in the top pipe under the cab being the second easiest.

I dont like the idea of doing that with aluminum heads, I just have this gut feeling that its going to pull threads out trying to force it. I haven't messed with the pipe since this post was made but now that I am getting close to getting the engine in the truck I need to consider messing with it to try and fit it.

Part number how ever for the one I got is 2020057 that comes with the converter as well but the converter is a slip fit and I wont be using it on mine. I have to get the engine in and the Y pipe mounted then get my Magnaflow muffler hung on the OE bracket then measure what length pipe I need to get. Dont want to get too short a pipe but I also dont want to go way over size and spend money I could better spend else where.