vh tacho pin selection

[TY318]

i recently replaced my vacum gauge for a tacho and i cant work out how to connect it would i have to do the wiring myself and i also need to know what pins are what

[VK SL 3800]

On a VK top is earth, middle is signal/negative terminal on coil and bottom is positive from ignition.

[TY318]

On a VK top is earth, middle is signal/negative terminal on coil and bottom is positive from ignition.

thanks mate ill try wirering it up myslef