The original exhaust valves from the 308 2 valve motors are sodium filled. They are known to break unexpectedly even when just accidentally dropping them on the floor so to be safe I ordered new replacement valves without the hollow stem filled with sodium. Then I decided to play "Mythbuster" with the old valves. I couldn't break them by throwing the valve to a brick wall, so I threw a brick on it and then it broke, but not at the weld. Placed in water the sodium started to bubble. I cut open the stem and the resident sodium started to burn. But the valve looked perfectly OK to me, no inside corrosion.
New exhaust valves and all new guides and seals. 1 inlet valve turned out to be seriously bend, so I ordered a new one. Had the valve seats cut by the machineshop, everything else I could do myself with basic tools.
I orderd slightly longer valve springs from a catalog for the inlet valves to get more closed seat pressure to outweigh the boost pressure but the orientation of the winds was the other way around and due to the slightly larger inner diameter I couldn't fit them really well on the retainers, so I decided to use 1 mm shims under the bottom retainers instead for the inlet valves. It seems the standard springs are good up to 18 PSI of boost and I plan 14.7 PSI max (1 Bar) so the 1 mm shims give some extra margin.
I thought the original motormounts would be to soft for the increased power and weight of the supercharger and then I read about Ford Mustang upgraded motor mounts by Prothane. They are made from aluminium with very stiff urethane bushings, I ordered them from Summit Racing USA. The bolt spacing is slightly larger and 2 mounts need to be trimmed down some and the other 2 need a spacer. I enlarged the mounting bolt hole to M12 so I could use the original mounting bolts.
