I just got flanges from RPM. Tubing I used the extra thick from Siliconeintakes.com I just got done building the passenger side, PITA for sure.
If I could offer some advice, unless you have a lot of experience in this, I would just buy them from RPM or even stick with the stock manifolds if you can. It really isn't worth it. I realized I could do a set of headers for about $600. Problem is, after changing my mind 3 and 4 times, I have now spent $2400 on this stuff. These changes came only after running the truck with them and realizing there were issues, you really need to think as far forward as possible before starting this project. I could have bought the RPM headers by now but in all reality, I really wish I would have just left my stock manifolds on.
It's great you can TIG, I am a Migger myself but neither skill necessarily makes us header builders. Determining angles, things like that with the engine in the vehicle is a PITA, determining angles with the engine out of the vehicle is a PITA because you don't have the frame etc. to show you where you really need to go. Just little details like that are why I say just buy something. Otherwise, it's a trap.
