One of my M's has a real finicky ground. Take the ground off and take a wire wheel to the area where it grounds. How long of cables did you buy? If you want to go fool-proof ground it on the starter mounting bolt.
Those M's always start in the winter but that fan sure blows the cold wind. Ever day I swear I am going to take the time to take the nose piece off and cover the rad, but I never do.