The early Honda N600 that was imported into the US in 1970-1972 had a 598CC air cooled twin in it.
They were around 40 HP weighed around 1300 lbs and had a top speed around 75mph.
I remember looking at one on a dealers lot and was amazed that a car had basically a motorcycle engine in it. At the time I was riding a Honda CB350.
The first car I purchased in 1973 was a Honda Civic. It had a real car engine in it which was water cooled with four cylinders and around 1200 CC. It weighed around 1,500 lbs. Both are tiny compared to my current Honda Fit which is classified as a sub compact car but weighs around 2,600 lbs.