When I lived in the Yukon I had a 1976 Civic that had a battery blanket, block heater, oil pan heater and circulation heater. I cut out the OE battery pan and welded in a lower pan to allow the installation of a Cat battery (about twice the size of the OE unit). That car would start at -55C and drive on it's square tires taking every ounce of muscle to shift gears and making NO heat for the first 20 minutes of driving.