I wouldn't bother trying to start a high performance car in such temperatures. On the other hand, my carbureted daily drivers from back in the day usually started, even in colder temperatures.
One of the best was my 73 T-Bird with the 460 4 bbl engine. Didn't require plugging the block heater in down to about -35? F!! Just turn the key, let it ssssllloooowwwwlllllyyyy turn over 3-4 times and it usually started.
next go back into warm house for 20 minutes while it warmed up.
For the record, I only did that a couple of times just to ensure it would start when that cold. Having the strongest, biggest cold cranking amp battery is a must up here.