Fabricating a Turbo Exhaust Manifold

When I decided to put a turbocharger and EFI on the rail, a new exhaust system that could support the turbocharger was needed.  Research showed that many people using the Ford 2.3 have good performance (up to 400HP) with a ported stock turbo exhaust manifold, but few of the prized "E-6" castings are available and would still require much time to correctly port. These stock manifolds also locate the turbo towards the rear of the engine rather than the center. Most sources agree that an equal-length tube header is not as important to turbocharged performance as it is in normally aspirated engines.  Of primary importance in a turbo exhaust is heat (energy) retention and delivery of that energy to the turbine.  I decided on a log-style manifold using schedule 40 pipe and weld-els, and flanges cut from 3\8 thick steel.  The thickness of the schedule 40 pipe and els will help retain heat and provide enough strength to support the weight of the turbocharger. 

Here's the various pieces for the manifold: flanges, weld-els and schedule 40 pipe cut to length.
I obtained a dummy head from a junkyard and used it for mock-up and as a welding fixture to prevent warping.
The flange and part of the exhaust
More mock-up
A general idea of the finished shape. From this point, exact measurements and dimensions were made and the cutting and fitting of the pieces began.
Drilling the holes in the center section
The center section with a square hole slightly larger than the t-3 inlet flange.  I made the square hole with a  plasma cutter (get one!) and finished it on the mill.
Here's the turbine inlet flange getting welded to the center section of the manifold.  3/16" steel plate was cut to fit and welded into place with generous use of heat and filler material to allow for smoothing and finishing the inside.
The turbo flange inside view, smoothing and rounding of all edges and corners has begun.  A carbide bur in a 1/4" electric die grinder was used to create this finish.  The electric die grinder was a great help, although slightly heavier than a pneumatic die grinder, it does not need a noisy compressor.
A semi-finished exhaust port on the header.  This will be finished to match the port in the head.
The mostly-finished manifold. 
Another view of the manifold.  It still needs a wastegate port, but it needs to be mounted to the car to check for clearance and interference before marking and welding. 
The manifold on the car showing the wastegate port with wastegate attached.  After all the welding, I took the manifold to my machine shop, R'n'R Machine in Phoenix, and they machined all the surfaces flat to assure a good seal between the head and the manifold, and the turbo and the manifold.