A good running 617 should never have to be plugged in in Johnstown. My '83 300D doesn't even have a block heater. If the engine is in good shape, the valves are adjusted, all the GP's are working, and you can use synthetic oil, that car will start in any weather.

Last winter, just to test it, as the car is garaged, I left it outside one winter night when the temperature the next morning was 8 deg.F. Without even touching the throttle, the engine starts in about two revolutions- with a six year old battery.