header material - stainless steels

[Jakey]

With a simple Google search, I believe they are the same thing:
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=Q304A

What have people told you in the thread you posted about this on Toonerz?

[Halon]

We just built a manifold for my buddy using Sch 10 bends. Turned out pretty nice, and over the next winter I'll probably be making one for myself.

[sleepydsm]

321 is better than 304, for exhaust manifolds (especially with sustained high heat applications). This made me wonder some stuff, so yes, I whipped out my Machinery's Handbook. I read alll about different types of stainless steels; 304 is a low carbon version of 302. 304N is the stongest 304 you can get. blah blah blah. Just make a header out of Inconel and be done hahaha.