turbo headers

[curious]

im thinking of building a tt318. what kinda material and dimensions do i need to use (thickness and diameter and such and what metals?) i found a cool machine at my precision machine class. you draw a picture with a black marker on white paper and lay it out and place a piece of metal under this torch and it cuts a exact duplicate. i could trace a exhaust gasket pattern and lay out the port and cut out a set of header flanges rather easily. also if i use schedule 40 primaries will i have problems with disimilar metals? the type of header i plan to build has the 4 primaries run straight out into another pipe with a dump at one of the ends. i think they are called "log manifolds"??? sorry that most of you have no idea what im talking about

[feets]

a log manifold made from schedule 40 would be an excellent piece assuming it's stuck together well.
Turbo Dodge has good answers to home made manifolds.
It's been discussed here before. Try doing a search in this forum.