Red hose from the distributor cap to the firewall is a distributor cap vent. Later 2F's have a vacuum system that will evacuate the (potentially explosive) ozone generated in the dizzy and send it through the carb to be burned in the cylinders. ; not sure what year that started though. Some people have been known to (mistakenly? Ill-advisably?) delete this system as part of a de-smog.
There's no sucking going on in yours, just a passive vent. The late system (as on my 1980) pulls air/gasses from the dizzy and dumps them into the air cleaner.So the explosive gases are sucked into the cabin ?