Damn, must be one of the earliest 3FE heads. Anyone know when production on the 3FE began?
Got some more time in on it this evening. The silicone mould-making process has started. I'm using a product called Mold Max 40. It's a 2-part product that you mix up similar to epoxy, and is supposed to cure in 16 hours. This particular variety has quite a thick consistency, flowing like a very think cake batter.
To save a bit on the amount of silicone used, and to hopefully make removing the mould easier, I used wax covered wire to fill part of the port runner space. I cut and bent coat hanger wire to the general shape of each port runner, then built up wax on it by dipping in melted wax, then cold water, and back and forth, ....... like candle making. After building it up thick enough, wax was removed off the ends so that the bare wire would sit on the valve guide at the valve end, and poke through a hole in the acetate film taped over the port at the other end.
Sticky-tac was used to plug the spark plug holes, partially fill in indentations for the air injection ports, and to hold the valve end of the wire/wax doo-hicky.
A couple pictures of the head prepared for the silicone. Overhead projector transparencies were used to cover the ports. I should have been more careful in cutting them to size and taping them in place, as I did get some minor leaking around them, remedied (somewhat) by wedging pencils in to hold the acetate tighter the the side of the head.
For the first portion of the mould, the head is upside down, with the manifold mating surface sitting lower than the spark plug side. The port runners were filled to approximately the level of the valve guides. Once the silicone sets, I'll remove these moulds (may have to melt the wax to allow more flexibility of the silicone into the resulting void), clean up the valve end and add some indexing depressions, re-insert them, add some release agent (Pam

) and make the second portion of the mould (the combustion chamber and valve bowl).
I've decided to make a mould of the CC and intake and exhaust ports for #4 (which will be the main cylinder used to test flow enhancement) and only the CC and intake ports for #6 and #2 (these 2 have the end member geometries for the intake runner approach angle, these will be used to test ways of balancing flow between the 3 geometries).
Hopefully tomorrow night I'll get the second part of the moulds poured, and can post pics of them on Sunday.

I guess I should make a 2-part mould of the intake valve while I'm at it, so I can cast epoxy valves to test different possible turned profiles.

Curtis.