The old cars weren’t that bad when it comes to rear end collisions. Just off the top of my head I can relate two of them. These both happened back in the early 70s.
A drunk traveling 60 MPH plowed into a stopped police car from behind and shoved the rear bumper clean up to the rear seat. Passenger cabin intact. Both cops went to the hospital with minor neck injuries and the drunk went to jail.
At Bouse Junction (in the Glass Mountains of OK) I came upon an accident at the stop sign which is a few miles south of the Little Sahara sand dunes.
A cash register rep had plowed into the back of a stopped Buick with a Chevy station wagon while also running about 60 MPH. The bumper of the Buick was pushed up to the back seat and the Chevy was in surprisingly good shape considering the impact. Neither driver was injured and turned down my offer to haul them in and get checked out at the hospital which was about 40 miles away.
When i wiped my '59 Corvette out against the side of a Chevy pickup I was running about 50 when I hit them.
Lap belts only; neither in use which was common at the time. The car was annihilated from bow to stern and neither me nor my passenger suffered even the tiniest scratch or bruise. Cabin intact. Rest of car shredded as it essentially exploded on impact.