What happens to an engine during a cold start in sub-zero temperatures?

Back in the 80’s i had a 68 coronet 318. -40 in canada is the same in f. Parked wth nose of car in snowbank. The gear reduction starter really shined on those days. If it would turn it would start. Had to do the dance on the gas pedal though.

had an 86 lebaron gts 2.2 turbo that would start in the lowetst temps too. But it got 0w20 synthetic diesel oil in the winter. That thing had wicked heat too.