If you look at this post from July. You will see how the finished motor will look. Rather then spend lots of $$ making the simple upper section I only had the lower part printed with DMLS. The upper section where the cat pack will go is fabricated in the normal way from a sanitary fitting. It will and then be welded to the motor bottom.
The horns sticking out the side are the fuel feed. The fuel goes in the curved part and a 8-32 Set screw with a orifice drilled in it goes down the straight section. Then the end of the straight section gets plugged. You can buy predrilled orfices in 8-32 set screws from Mcmaster Car.
Here is a picture of all the bits before welding:
The two small parts are the machined elbows to connect the vertical feed tubes with the Chamber top.