My 1967 BJ8 which I just acquired came with a Mallory dual point distributor. The car is still pos earth and it runs fine. The problem is that the Smiths RVI tacho is reading WAY high (perhaps double). This I suspect is due to the Mallory dual point dizzy.

Does anyone know know how to wire a tach on a pos earth car so that it will work properly with a Mallory dual point distributor.

Regards,
Michael