Are you running 12 volts? Do you have an inline resistor before the coil? Some points can't handle more than the rated voltage and if your alternator/generator is putting out say 14-16 volts it causes them to overheat and burnout quickly.
Don't worry about the frost on the intake. See that all the time with no issues. Depends on humidity and temperature and all that.
If points and all look good. Then go to the manifold leak or head gasket leak. While running, Spray carb cleaner around intake gaskets and seen if that changes engine running speed. Then you know you have a leak.