Never learned to weld, so have to have this done by others.
Have done (or designed) several manifolds such as the one being discussed. Our solution is: aluminum conduit (thick wall) as has already been suggested; conduit bends for the angles; junk carbs for the flanges (Carter BBS and BBD made for Chrysler give a number of different 1 and 2 barrel flanges).
Have never had to do any bending. Just saw (or mill) the various pieces to fit, and take them to my local welding shop.
Manifold heat is not generally necessary with ambient temperatures above 50 degrees F. For lower temperature, fab a sheet metal aircleaner, and have two inlets: one from a fabricated sheet metal "stove" on the exhaust manifold or headers; the other to open air.
You need the equilization tube on the street!
Sounds like a fun project. Just do it!
Jon.
