The 2nd Generation Chevelle SS started in 1968 with a refresh of the Chevelle Malibu body and continued to see refinement each year through 1972. In 1968 and 1969 the Chevelle SS-396 was still the standard continuing with 3 different levels of performance with the L35 putting out 325hp, the L34 at 350hp, and the solid lifter L78’s very dominant 375hp. The Yenko and COPO Chevelle also made waves and featured a 427 L72 with output of 425hp. In 1970 the muscle car wars would reach their peak with Chevrolet introducing the SS-454 with loads more torque, which brought 2 variants of the LS5 offering of 360hp, and the legendary LS6 with 450hp in addition to the SS-396 offerings. These options also carried over to El Camino SS.  1971 and 1972 saw more federal emissions starting to take hold, and lower performance output, which also resulted in the SAE net horsepower ratings decline which would also signal a change in how manufactures would report the output horsepower in 1972 onward.  The upside for buyers is they could now get a 350ci small block option and have the Chevelle SS name plate. The Chevelle would make one final push in the 3rd gen Chevelle SS.