I am planning on trying my hand at making a manifold.
I know where to get materials, i am just not sure what specifically i need.
What is the common tubing size used for these projects(ramhorn, log, top mount)?
has anyone plasma cut there flanges, is this ok?
Is 3/8s 304 ss thick enough?
thanks ahead of time, i actually did search for this info for awhile b4 posting.

 

Well, I won't be the one to hand you the whole show. All these questions you have could be easily answered with the exceptional search ability of this site.

I will tell you that mild steel flanges are used in general instead of stainless due to less possibility for warpage. I've used 3/8's mild steel flanges cut with a plasma many many times without any issues. I just use a plate for the flange to bolt to when I weld on it so it doesn't distort.

Two and a half seconds of searching yielded me this

https://honda-tech.com/zerothread?id=956666