Header building help - oval at flange to round primary

Take the primary tube, oval it. Take 2 sockets that fit the oval and a cold chisel between them . Put this in a hydraulic press and press the chisel forcing the sockets apart. Use larger sockets to get the size you need. A little oil on the inside of the tubing helps.

 

love it

 

Absolutely! What Paul said! Stupid simple!

 

I ended up not making starter tubes. I ended up just working the primary tubes in-place. Mocked up the header, tacked it to the flange. With the flange and header unbolted, I tacked them to the inside and found that the metal worked real easy with even a moderate amount of heat. So a couple tacks, a ball decent sized ball peen hammer, and a small length of 1" round bar was all it took to work it around the inside of the oval. I'll post some pictures up in a bit.

 

Right on; that's the way to do it. Way cleaner. We don't need no stinkin' starter tubes!

 

Yep! Worked out good Hank!! Thanks for the tip! Amazing how far that stuff will stretch!

And because I had the headers mocked up first and THEN tacked the flange to the primaries, everything stayed put. The flange after all that heating and beating with the ball peen is still flat! the header acted like a support structure to keep it true.

 

Nice! Well done and much less work than creating the starter tubes.

The way you were describing doing it with the 1 3/4" inside the 1 7/8" would have made things very turbulent right out of the port.

BTW, what displacement is the Hemi and what horsepower are you expecting out of it? Just wondering how you decided on the primary tube size.

 

Nice job! Finish the outside with a nice tig weld using silicon bronze rod - looks great and adds support to prevent cracking. vic

 

I think that's the first time I have ever seen you use a exclamation mark in you 411 posts. You are never excited about anything but I guess exhaust rubs you the right way Vic haha!!!

 

The Hemi is a 331, punched out like +.035. Nothing crazy. Basically, I asked around, and looked at what other people did, but also did some comparison thinking to what a standard small block of similar port design and CI's would have. Nothing scientific. Open headers are not exactly a tuned exhaust system, but I wanted to be somewhat smart about what I chose because I will be running some cut-outs to 2-1/2" or maybe even just 2-1/4". I'm hoping to fall somewhere in the 325 or 350 range for hp. Nothing nuts. Only a Model A. But more would be cool.

And yes! FAR less work and stronger, I think. Had I actually decided to use starter tubes, I think I would have just made a bell-shaped form/die, heated up the tubing, and just pushed it over the form/die.

 

Can you take a pic of the flared tube from the outside?