1966 Mustang 2+2, 4 speed transmission, Speedometer runs backwards

I have a no numbers matching 1966 Mustang, 2+2, 289 ci., 4 speed manual transmission with reverse to the left and up. The speedometer cable installs to the RH (passengers) side of the transmission. Is there something I can get or do to get the speedometer to work properly, and not run backwards?