Too cold to start car

That's like putting a 60 watt light bulb is a chicken coop. LOL!
It's only max 200watts. Most block heaters are in the 500-1100 watt rage for a cast iron V-8.
Yes it will work but if left over night - from the day before.
Like putting lipstick on a pig. If the orig poster cranked on the engine for a half hour before the battery went dead he doesn't have a battery issue. If the friggen choke worked it would have lit on the third crank and we wouldn't be beating ourselves up over it. Heavy oil and all. Hell the plugs are probably dripping with fuel and the crankcase is a quart over full with gas. Clean the plugs, change the oil and filter, fix the choke and check for spark. Then go from there.