That's absolute nonsense.

I would believe you could get a 4-foot-wide item in a Civic.

There is no way on earth you could get a 4x8 sheet inside one of those cars.

Also, if you got t-boned by a Tahoe they would need to identify your body with dental records. Those things were basically street-legal go karts.

Sorry, i didn't mean it fit 100% inside. I meant that hatchback was, then unlike today, wide enough to slide it inside, and you could get enough of material inside to safely drive it home with the hatch tied down.

Today, this is no longer true of any "small car".