X frame vs new technology
As I restored and still own a X frame 1963 impala SS, this video is an eye opener for sure. The X frame was not the greatest design and is flimsy which is why GM stopped it after 1964 as the increased HP coming out was reaking havoc with the ol X frame. The 425HP 409's were pulling the upper control arm out of the frame, the stupid center carrier bearing for the drive shaft was another reason and the body cracked along the quarter panel where it meets the roof after a few years.
Why this test was done, makes me wonder but metal fatague, rust, worn out body mounts perhaps even replaced bumper bolts could all factor in. Seatbelts were not required until 1966 by the Federal Gov. so death statistics again are not apple to apple comparison as to how safe a car in 1959 was compared to today's car. The use of super computers and the Insurance Institue's work has no doubt made our cars much safer today. I vote for a retest with a 59 caddie !