I’ve gotten a 1956 bel air and after searing for the reason why my spidometer doesn’t work and just makes noise ive found that the cable connector is to big to screw into the spidometer how can I find another cable that can screw into the spidometer or make the one I have work
As @fluke said, eBay.
Assuming you are in the US: https://www.ebay.com/itm/230992925987
30 day return, you pay shipping.