The mid-sized Chevelle was based on reengineered A-platform and was one of the most successful GM’s cars that ranged from economical family cars to muscle-performance coupes and convertibles. All of them had friendly price tag and good performance. So, that let Chevelles, together with Pontiac GTOs, be one of the most popular street cars. The production took 1964-1977 period when the last year Chevelles were replaced by the Malibu [which first was the top level trim for Chevelle itself]. The early Chevelle drawings show that it probably would have ended as Nova nameplated cars, bacause the aim for it was to compete with equally sized Ford Fairline and other popular 55-57 models. You could get a retrimmed Chevelle based version called “Beaumont” in Canada from Pontiac dealers.
4-door Chevelle sedans were available in 1966-1972 together with dubbed Sport Sedans. The 2-door wagons were available in the bottom line 300 series back in 1964-1965, while the 2-door hard-top coupes and convertibles were produced a bit longer – until 1972. The entire run thought all Chevelle years was done by family friendly 4-door sedans and wagons taht had exclusive nameplates like: Nomad [1968-1972], Nomad Custom , Greenbrier [1969-1972], Concours [1967-1972] and Concours Estate [1968-1972]. The 2-ddor hartops were known as SCs [Spot Coupe].
The real SS deal
The Chevelle SS was the high performance model range with its own line of engines and performance equipment. The SS also represented GM’s entry to the muscle car battle with quita an engine range: 396 cubic V8s – rated at 325/ 350/360/375 HP. The SS396 lasted for 3 years only [including 66-67 LE strut back SC] and the become an option package. It is known that there were 2 prototype Z16 Chevelles and one convertible built in Baltimore plant [while the regular Z16s in Kansas City]. The one of the kind convertible [commonly called the 201st Z16 Chevelle] was built for GM’s general manager, but is know to be destroyed.
The Z16 option included heavy duty suspension, narrowed rear axle and brakes from Impala, convertible boxed frame. The standard Z16 engine was the big block 396 cubic Turbo Jet V8 available only with Muncie 4-speed manual transmission.
In 1966 the Chevelle was completely restyled – the body reminded Coke bottle shape. 2 years later, in 1968, Chevelle got an other restyle which made the very popular semi-fastback roofline. The SS396 became a separate model available only in SS and performance option from 1969.
Until 1970 GM had a policy not to put larger than 400 cubic [6.6 liter] engines into mid-sized cars, but Chevy’s dealer Don Yenko managed to ovoid this restriction by using COPO system and ordering L72 427 cubic engine [425 HP] with all necessary upgrades. Yenko sold them as his own muscle cars. But since 1970 GM dropped the restriction and started to put even larger engines. The result was an other SS option with 454 cubic [7.4 liter, 360 HP] or LS6 [450 HP] V8s. The new option was called SS454.
For 1971 Chevelle faced the same emission restrictions as all other cars, so the horse power went down after reducing compression. For example, the top engine back in 1972 was rated at 270 net HP. Officially… The was no evidence that that power had changed that year. Heavy Chevy was the 1972 appearance package with special striping and any V8 except 454 big block.