Gene, it is just a Malibu, not a Super Sport. It was born with a 2 barrel 283 and a powerglide.
Of course, it's the same basic car as a SS, in being it is a Chevelle. But in '66, '67, and '68, the Super Sport was it's own model, identified by the 1st three numbers in the VIN being 138. The Malibu had a VIN with the 1st three letters being 136.
The Super Sport models had that name on the rear quarters. Here is a good example of a true '67 Super Sport.
http://www.barrett-jackson.com/Archive/Event/Item/1967-CHEVROLET-CHEVELLE-SS-396-2-DOOR-COUPE-75259
Here is a Malibu.
http://www.barrett-jackson.com/Arch...EVROLET-CHEVELLE-MALIBU-2-DOOR-HARDTOP-117833
You are correct, all Super Sport models came with a Big Block 396, a 12 bolt rear end, and some other performance upgrades. Chevelle was the base model, Malibu was the upgrade from that, and Super Sport was the high performance model. You could not order a "Malibu" with a big block.
Those three years are the only years where the SS was it's own model. In '64, '65, 69, '70,'71, and '72, the designation SS was simply a trim package that you ordered and had nothing to do with what we recognize as "performance",
Of course, my Chevelle is a total custom restoration. None of the major components are original, , including engine, transmission, rear end, all suspension parts, brakes, steering, cooling system, and so on. The sheet metal is all originol, (minus the SS hood), and basic parts, but overall, it is a Malibu in name only.