1960-1962 Chevrolet - GMC question

[Huffstutler]

I have asked these questions on other forums but not received a definitive answer. Hoping that a specific forum like this one will have some insight or background to this?

For the 1960-1962 model year Chevy and GMC light duty pickup and Suburban’s, they utilized both a X frame and torsion bar suspension. I am curious as to why they chose a X brace design when none of their previous pickups had it, not even back in the 1930s-1940s, and this particular configuration of chassis was dropped by all GM lines by 1961. Some say it was directly associated with the torsion bars. Problem with that claim is that the bars were anchored to a cross brace running between the side rails and not linked to the X. The rear trailing control arms were hooked to the X but were then connected to yet another cross brace in 1963 when the X member was dropped. So there is no immediate rational reasoning for the X frame associated with suspension.

Another says that the torsion bars were dropped due to patent infringement when Chrysler sued GM. That is an urban legend because there is no record of that ever taking place and the first generation front wheel drive Cadillac Eldorado and Oldsmobile Toranado used torsion bar suspension. And, the designs were different yet not unique because they have been in use on US and European cars since 1921. I have not even found a specific patent on Chrysler’s production torsion-aire.

One wonders if the design crew was a bit overzealous in designing the frame not knowing exactly what to expect and even though they claim it was 400 pounds lighter than with the conventional ladder type, cost factors was the real demise of the X and torsion suspension?

Who was in charge of design for the 1960-1966 style pickups? Who was the engineer that approved the X frame chassis and why was it chosen over a ladder frame?

Lastly, does anyone have a good high res scan of this particular ad that at least ran in Ward’s Automotive – Volume 22 of 1960, page 147 ? Or similar?

Any help is greatly appreciated!