The only thing I ever read about them was the fact that the first gens were such a rush job that Pontiac was stuck with the mono-leaf rear springs that Chevy used on the Chevy2 and Camaro. Pontiac quickly realized that an engine/trans/gear combination with any real grunt would cause bad cases of spring wrap-up and wheel hop. The band-aid was the traction bars. By 1968, replacing them with multi-leaf springs solved the problem and the bars were deleted.