How do I mold this?
It is quite complex. The plenum part is simple I have made up a plug for a female 2 piece mold. I could make a flange out of plate steel or alu rather than the cnc’d flanges.
For the runners, I am thinking about shaping one runner in styrene and then takng a mold. From the mold, make 4 water soluble core (to keep thm exactly the same) for an overlay using Aquapour. I would fit the runner cores into flange at one end and on a sheet of MDF and fair it for a smooth entry into the runner for the overlay. Then fix to the plenum.
The metal flange for the opening is not required. The injectors are on stub throttle bodies.
This will be a learning experience! Is there another way(s)?