I am afraid it was not my idea. I was looking for mock up ideas and tripped across this... https://www.youtube.com/watch?v=9s1-AZcPWAA
turns out http://www.stainlessheaders.com/ is a sister company of GP Headers- http://www.gpheaders.com/. You rent the mock up header flanges, merge collectors, a dozen swivel joints, and some PVC angle fittings from GP Headers ($600 deposit). You can then weld up a fixture to hold the mock up, and use header pieces purchased from stainlessheaders.com or other vendors, and return the mock up pieces to GP Headers to get you deposit back, or ship the mock ups to GP Headers to have them fabricate the headers for you...

I made my headers on my Coupe. Made the flange patterns, made the stubs (hardest part) and then cut the tubes piece by piece and tacked where needed. Ran them to my buddy's shop where he tig welded them
Best thing I did for the car, everything fits and as much clearance as possible. I made mine equal length primaries, what a pain.

Love the progress pics, keep em coming!

A quick progress pic... The tunnel is basically done. Larger than I would like, and made without the nice things like a slip roll, etc.



The headers have been shipped from the fabricator and hopefully will be installed by the end of this coming weekend.

The tunnel looks good. Once you get carpet on it it will look like it was always that way.

Just noticed, was that a stick car you changed the column in or an automatic car you changed the dash on (to eliminate the shifter pod)?

you did a good job on the tunnel, and the shifter looks like it grew there. as was said, after the carpet is laid down, it will look like "factory". i know the deal about bending a tunnel without a slip roll, as i did my driveshaft and transmission transition tunnel sections the old fashion way by wrapping around anything that was the shape i needed to get what i wanted. and using 16ga. material, that was a mighty chore indeed ! then after it was completed, i stumbled into a power slip roll that was disassembled and being tossed in the junk ! well, that was grabbed, and almost 100% of the parts were there. and it works great ! but if only i had it then.........

Thank you for posting, ......it keeps a lazy old dog motivated!

So much so that my Dakota is finally in the early stages of disassembly.

The headers have arrived. I hope to trial fit them in the car tomorrow...





Mike P- “The tunnel looks good. Once you get carpet on it it will look like it was always that way.

Just noticed, was that a stick car you changed the column in or an automatic car you changed the dash on (to eliminate the shifter pod)?”

Thanks. My car was an automatic with the two speed powerflite. I have been running a TF727 with a manual valve body and Lokar shifter for the last15 years or so.

Moparx- "you did a good job on the tunnel, and the shifter looks like it grew there. as was said, after the carpet is laid down, it will look like "factory". i know the deal about bending a tunnel without a slip roll, as i did my driveshaft and transmission transition tunnel sections the old fashion way by wrapping around anything that was the shape i needed to get what i wanted. and using 16ga. material, that was a mighty chore indeed ! then after it was completed, i stumbled into a power slip roll that was disassembled and being tossed in the junk ! well, that was grabbed, and almost 100% of the parts were there. and it works great ! but if only i had it then........."

Thanks. It seems like you never have the right tools for the job, no matter how many tools you have.

Old Ray- "Thank you for posting, ......it keeps a lazy old dog motivated!

So much so that my Dakota is finally in the early stages of disassembly."

Your welcome. I seem to benefit from doing a little bit as often as possible, rather than long marathon sessions of building activity. I dont burn out as easily. Good luck with your project.

It is no fun getting them in..
I am going to have to dimple the tube for cylinder #6 due to starter interference.



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Looks like they fit like they were made for that location. LOL!

Was dimpling the tube for starter clearance an issue with the header build, or the fixture you sent them, or was it for clearance during installation?

At this point, would you go this route again?
Gene

I am pretty sure it is the result of the mock up moving during shipping. For example, the tube for cylinder #2 seems to have moved closer towards the valve cover at the turn down towards the collector. I struggled getting the mock up rigid enough to prevent movement in this area during its construction. It doesn't take much movement at the header flange to make a big difference 8-12 inches away from that point.
The PVC was touching the starter when I did the mock up. I had hoped that the difference in O.D. between the schedule 40 pvc and the 1 7/8" primary tubes of the final product would provide sufficient clearance. It would have been very tight under the best of circumstances. I had figured on possibly having to dimple a bit. I had the UPS store package the mock up for shipment, so I did not control that part of it.
I have since dimpled the tube for the starter clearance, and may contact the fabricator tomorrow to see about modifying the header. It isn't bad at this point, and I am not sure it is worth the hassle. In short, I would do it again, but probably would consider making a jig to hold the mockup securely for shipping to ensure no movement. I considered it prior to sending this set, but got in a hurry/lazy.

......just thinking (always dangerous).....sheet metal screws at the connectors or PVC glue if they didn't have to be disassembled for construction ???

Sheet metal screws were used. Truth be told, one of the areas most susceptible to play is at the swivel connectors where they screw into the stubs at the header flange. The stubs and the swivels are threaded, but the swivels are made of aluminum and the stubs are steel. To help address galling and also probably due to repeated use, the threads are not very tight, allowing movement. In some cases I drilled into both the stubs and swivels and ran screws in to try to stabilize things, which seemed to help. You would not think a little play in the threads would make much difference, but at the other end of a lever, it adds up. combine that with a very restricted installation location for the tubes, and it doesn't take much to cause some interference.

Actually, if that one tube is your only issue, I think it came out pretty good. Most production headers on a standard set up have at least one issue someplace (unless the header quality has improved dramatically in recent years). Gene

I would agree. Looking at tables of dimensions for schedule 40 pipe shows an outside diameter of 1.900". I went with 1.875" primary tubes. That provides only .0125" of clearance added when switching from the pvc to the stainless tubing. I thought I measured it with calipers and there was more difference than that... but? I cant even say for certain that there wasn't some tension in the mock up pulling the #6 tube further toward the starter after everything was unbolted, as it was contacting the starter and I didn't do a whole lot of yanking on it to see if it was a little bound up.
Then throw in movement of components of the mockup during shipping, regardless of how many screws I put in to hold it together... It had to survive a trip from Washington state to Minnesota with who knows how many transfers on the way. Then you have to build a welding fixture to hold all of the new header components in the same location as the PVC mock up parts, cut and fit each change in direction of each tube so it all fits correctly, then finish weld everything hoping the heat does not pull anything too far out of line. Add to that a very restrictive final install... Cant really complain too much. If I had chosen 1.625 primaries it would have helped. I could have routed one or more tubes out of the frame rails and into the fender wells to give a little more room. There are other configurations that would have been more complicated but provided some wiggle room. The dimple will cost me zero horsepower. The only downside really is that I feel compelled to ceramic coat the headers to help prevent heat soaking the starter, which adds cost to what is already an expensive exhaust system. I could have saved some money by going with mild steel instead of 304 stainless, and gone with formed collectors rather than merge collectors for those of you pondering a similar project..... The price difference in materials and components would probably offset the cost of the coating, which is $345 for a pair of long tube headers by http://performancecoatings.com/ in Auburn WA.

they turned out very nice in my opinion ! you did a good job mocking them up. do you have a pic of the dimpled area by the starter ? would it be possible a simple [simple being a relative term of course :grin] heat shield could be fabbed for the starter, or the starter wrapped with some kind of shielding wrap ?

I would take a picture of the dimple, but I boxed and shipped them for coating... kind of want this part of it over already.

awesome man

Headers have returned from ceramic coating:

Its tight.

Now for the bad news... I am getting into the hood with the intake manifold near the throttle body.