For this build there will be no tachometer. We therefore need to blank off the mechanical tachometer drive hole in the head. I designed a special plug that fits the hole and uses the same o-ring as the stock insert. This plug is then clamped in place with the stock bracket and an M6 bolt. Shown below is the original set up plus a couple of plastic prototypes I printed and then the real prototype turned up in aluminium. Then a shot of it in context :)