The Aspen/Volare twins were light enough that with certain engines, they were rather potent--tests from car magazines of the day revealed that the 1977 360-engined Aspen, with a two barrel carb, was about on a par from zero to sixty miles per hour as the 1977 Camaro Z28 and Corvette L82, both with four barrel 350s.
All three of these cars were faster than the 1977 Trans Am 400-4.
The Aspen was a bit slower by the clock but faster through the traps in the quarter mile than all of the other three from GM.
The 318 offered more sedate, everyday performance. It was obviously less powerful, but it performed about the same as its competing models with similar-sized engines of the day.