Radiator Question

It would pay to try to determine the cause of the overheating, IMO, before buying a new radiator, unless of course it's leaking. 1970 year I'm not real familiar with, but if a new radiator is decided upon, I would consider several factors. Condition of the coolant can be a tip-off; is it very old, is it relatively clean-looking? Second, engine size, you did not mention. Big engines need big radiators. If space permits, upscaling the replacement radiator to more rows of core is not a bad idea. Check the mounting of the radiator, if leaking, force applied to radiators by flexing of mounting parts can destroy their sealing integrity. Replacing the radiator simply to remedy an overheating problem will only be successful if the old one is partially clogged. imp