Compulsive chicken choker
Manufacturers didn't have towing limits back then, BUT be aware that American towbars (trailer hitches) for "normal" family saloons are often only rated to 2000lbs (about 800kg) and are (at best) rather flimsy, being designed to bolt onto wherever is convenient, rather than where is strongest. Some of them simply clamp to the bumper. I'd get one made by a UK towbar specialist (Watling Towbars are good).If I was to get a tow bar on my '65 Mustang how would I determine the maximum towing weight given there's no weight plates at all? Wikipedia suggests a kerb weight of 1400kg.