Header Fabrication

-
mopowers

mopowers

Well-Known Member
Joined
Feb 15, 2006
Messages
8,528
Reaction score
4,723
Location
West Sacramento, CA
For those who have built their own headers, do you have any tips or tricks for forming the primary tube to the exhaust flange?

A vise and hammer seem to work ok, but I'm curious if there's an easier way. Thanks guys!

upload_2021-9-12_17-10-43.png
 
Heat and beat is the only answer! And I have built a total of two sets in my life as a welder and fabricator. Translated I have better than average skill. Ask me if I will ever build another set? Not only no but heck no. First set was for a Pontiac set of heads, fabricated a three pipe set for a V8 to eliminate center leak. Next set for for a Porsche race car competing in D production SCCA. I was on pit crew so did not really have a choice. Fabricating headers is a tuff gig period! Good luck!
 
To quote the late, Great Tom Hoover....."everyone should have to build one set of headers, but no one should have to build more than one set."
 
Sublime one said:
Heat and beat is the only answer! And I have built a total of two sets in my life as a welder and fabricator. Translated I have better than average skill. Ask me if I will ever build another set? Not only no but heck no. First set was for a Pontiac set of heads, fabricated a three pipe set for a V8 to eliminate center leak. Next set for for a Porsche race car competing in D production SCCA. I was on pit crew so did not really have a choice. Fabricating headers is a tuff gig period! Good luck!
Click to expand...

Luckily for this set, I'm just putting together a glorified set of log manifolds just to get the car running. I may try to make a "die" to clamp the tube with in the vise that forms it to the right shape. I'm curious if anyone's done that before and has any tips.
 
One thing that on serious note will actually help you vs our sarcastic wit is to fabricate a “horn “ that matches the rectangular size you are trying to fit to. Then as you heat and beat pipe to fit you can have a template if you will, to test fit while still hot. And the Tom Hoover quote is as relevant today as it was back then. Straight up fact! You think fitting to the rectangular port sucks wait till you get in some tantric yoga positions with a mirror to weld the mitre.
 
Try and form a mandrel...whittle down a bat end or something to beat the metal to shape on. Beat it!

Jennifer Batten didnt\'t do solo on album...Eddie did.
 
Some people are not satisfied with getting water from the tap or faucet, thay have to drill a new well.
Good luck!.
 
Some good tips from 900HP and Exhausted (Calvin Elston) if you skim through here 340 Chrysler Street Header Questions - Don Terrill’s Speed-Talk toward the bottom of the first page and then onto the later ones for what you are asking about blacksmithing.

Probably more in this thread - I can't recall for sure if the flange to pipe fitting was discussed.
First time header build - Don Terrill’s Speed-Talk

As long as the pipes off the flange are reasonably long enough, the log header can work very well.
See Calvin's posts about blowdown, and if you're a member, follow Hoffman's link to Clavin's thread about when he tested the theory using by making log header. If not a member, Hoffman quotes snips that cover the takeaways/
Novice exhaust question: What is "blowdown length"? - Page 2 - Don Terrill’s Speed-Talk

Another source of tips on welding up flanges and pipes is Headers by Ed. If you can get past his curmudgeoness, he built nice stuff. Not sure whats on his website but worth poking around.
 
Mattax said:
Some good tips from 900HP and Exhausted (Calvin Elston) if you skim through here 340 Chrysler Street Header Questions - Don Terrill’s Speed-Talk toward the bottom of the first page and then onto the later ones for what you are asking about blacksmithing.

Probably more in this thread - I can't recall for sure if the flange to pipe fitting was discussed.
First time header build - Don Terrill’s Speed-Talk

As long as the pipes off the flange are reasonably long enough, the log header can work very well.
See Calvin's posts about blowdown, and if you're a member, follow Hoffman's link to Clavin's thread about when he tested the theory using by making log header. If not a member, Hoffman quotes snips that cover the takeaways/
Novice exhaust question: What is "blowdown length"? - Page 2 - Don Terrill’s Speed-Talk

Another source of tips on welding up flanges and pipes is Headers by Ed. If you can get past his curmudgeoness, he built nice stuff. Not sure whats on his website but worth poking around.
Click to expand...

Thank you for these sources! I'll definitely read through them. Thankfully, I've got a ton of room since the inner fenders have been removed. I'm not worried about giving up any power now since I'm just wanting to get the stock 400 driveable. The plan was to build a proper set of long tubes (likely 2" primary) when I build the 470/512 (haven't decided yet).

upload_2021-9-22_17-37-10.png
 
If your headers are going to be temporary until your next motor is done, but a set of cheap headers with the tubes already formed and in place. Cut off what you don't need and use the leftover somewhere else on the headers.
 
For those who have built their own headers, do you weld the inside where the primary enters the header flange, or you weld around the perimeter on the outside, or both?
 
Built plenty of headers.. I’ll charge double on a mopar lol. Either way you’ll have to hammer form to start. The 90* edge of a table works well. Just have your rotation right before you square the tube.. after use a hammer and a punch on the inside to seal the rest to the flange so it’s an easy weld. Weld both outside and inside. Mildly port inside to make smooth/ belt sand flange flat(important). Other option is to put them on a mill (cnc) program a .125 step into the flange that’s round! Blend back the inside with a carbide bit. I don’t use a gasket on mine just high temp rtv. Flange HAS to be flat though. 318 port on the pics. Much harder than a 440 port
D06E38CF-DA9A-47DD-B5AB-0609ECAE6D23.jpeg
A5543324-6E45-480A-A5D8-F862D8B00E73.jpeg
157F2174-B12C-49E0-9031-1E4296AF42D1.jpeg
B17964DF-21F3-4456-96B6-B48459F2BD65.jpeg
 
SlantedDart said:
Built plenty of headers.. I’ll charge double on a mopar lol. Either way you’ll have to hammer form to start. The 90* edge of a table works well. Just have your rotation right before you square the tube.. after use a hammer and a punch on the inside to seal the rest to the flange so it’s an easy weld.
Where about are you in Michigan.
Click to expand...
 
SlantedDart said:
Built plenty of headers.. I’ll charge double on a mopar lol. Either way you’ll have to hammer form to start. The 90* edge of a table works well. Just have your rotation right before you square the tube.. after use a hammer and a punch on the inside to seal the rest to the flange so it’s an easy weld. Weld both outside and inside. Mildly port inside to make smooth/ belt sand flange flat(important). Other option is to put them on a mill (cnc) program a .125 step into the flange that’s round! Blend back the inside with a carbide bit. I don’t use a gasket on mine just high temp rtv. Flange HAS to be flat though. 318 port on the pics. Much harder than a 440 portView attachment 1715811600View attachment 1715811601View attachment 1715811602View attachment 1715811603
Click to expand...

These are great tips! Your headers look awesome!!! For these logs, I just ended up using my bench vise to squeeze the tube one way, and a big pair of vise grip clamps to square it up the other way. Then a big punch and hammer to make adjustments. It turned out working pretty well.

upload_2021-10-27_18-42-41.png


Since I wasn't sure whether to weld the inside or the outside, I did both just to be safe., then ran a flat file over it to ensure the flange was perfectly flat. I just wish I had a good friend who was a good tig welder. Hopefully everything seals.

upload_2021-10-27_18-44-14.png


upload_2021-10-27_18-45-10.png


Lastly - don't ever buy j-bends from Hooker. I couldn't believe how rusty these were on the inside.

upload_2021-10-27_18-46-47.png
 
mopowers said:
These are great tips! Your headers look awesome!!! For these logs, I just ended up using my bench vise to squeeze the tube one way, and a big pair of vise grip clamps to square it up the other way. Then a big punch and hammer to make adjustments. It turned out working pretty well.

View attachment 1715811618

Since I wasn't sure whether to weld the inside or the outside, I did both just to be safe., then ran a flat file over it to ensure the flange was perfectly flat. I just wish I had a good friend who was a good tig welder. Hopefully everything seals.

View attachment 1715811620

View attachment 1715811621

Lastly - don't ever buy j-bends from Hooker. I couldn't believe how rusty these were on the inside.

View attachment 1715811622
Click to expand...
Great work. It looks really nice.
 
You could always make it easy on yourself and just buy the flanges with 1" stubs.
 
You must log in or register to reply here.
-

Back
Top