Heat from engine inside car

[roy green coupe]

On my 30 coupe I noticed hot air coming into the cab from under the fuel tank at the ends. I found it was coming in at the lower body corners just below the floor and up behind the kick panels . I sealed it up in an effective but not period correct way with insulating foam. It is much cooler inside now, bottom of fuel tank actually feels cool. My question is how was this addressed in the original cars ? Did they have some kind of seal or insulation that would have taken care of this?