cable drive tachometer

i have an old dual point with tach drive, question, is it just direct to tachometer? or does it need one of those sw reducers, also, where does one get a cable, short one

 

Do you have a picture??

 

Whether or not you need a gearbox depends on the needed tach drive speed, and the ratio of the drive gears in the distributor. If the tach reads correctly as is then you are fine. If not, a gearbox, or tach servicing, is needed.

 

You can get a cable made up at almost any speedometer repair shop.
Get the cable and hook it up to see how your head is calibrated.
Then you will know if you need a doubler.