1966
The first year of the SS396 saw three engine options, all 396 V-8s. The base SS396 engine was rated at 325 hp, an optional RPO L34 was rated at 360 hp, and the killer RPO L78 was rated at 375 hp. The L78 was released to dealers in February 1966 with no public advertising until later. A heavy-duty 3-speed manual transmission was standard with several Muncie 4-speed transmissions and the venerable Powerglide 2-speed automatic behind the base 396 and the L34 engine option. The L78 engine could not be ordered with a Powerglide.
The Buick, Oldsmobile, and Pontiac divisions were playing along as well. The 1966 Pontiac GTO was now its own series and no longer an option on the Tempest. The Oldsmobile 4-4-2 option had a new 400 V-8 rated at 350 hp and a tri-power setup that boasted 360 hp. The Buick Grand Sport was still an option on the Skylark.
1967
Aside from some styling changes, the 1967 SS396 engine lineup was about the same as in 1966. The L34 360-hp engine was downgraded to 350 hp and the new TH400 3-speed automatic transmission became available and could be had behind any 396 engine in 1967. The L78 375-hp engine was initially dropped from the option list but returned without much fanfare in April 1967. As a result only 612 L78 engine options were sold in 1967.
This 1967 SS396 sport coupe is in the one-year-only Royal Plum. This was the first year for the TH400 Turbo Hydra-Matic transmission and disc brakes in the SS396 Chevelle. (Photo Courtesy SS396 Registry)
The Pontiac GTO dropped the tri-power carburetor setup in favor of the Rochester Quadrajet 4-barrel carburetor. The engine was increased to the GM corporate limit of 400 ci. The Buick Grand Sport became its own series but still offered a variety of engines with the 401 V-8 at top of the line. The Oldsmobile 4-4-2 continued to be an option on the Cutlass platform.
1968
The 1968 model year was the first and last year the SS396 El Camino was a separate series along with the sport coupe and convertible. The same three 396 engines were available with the 325-hp version being the base engine and the L34 and L78 being optional. The 2-speed Power-glide continued to be an option behind the base and L34 engines.
SS EQUIPMENT OPTIONS 1969–1970
In 1969 the SS396 Equipment option became just that, an option, even though it was still commonly referred to as an SS396. The 1969 model year was the only one that the SS396 Equipment option could be ordered in a series other than the Malibu series. The 1969 300 Deluxe coupe (13427) and 300 Deluxe sport coupe (13437) could be ordered with the SS396 Equipment option package.
The year 1968 was the only one that the SS396 El Camino was its own series rather than an option. A 1968 SS396 sport coupe in Matador Red is shown here with optional D96 side stripes. (Photo Courtesy Dave Meehling)
Numerous automatic transmission options were offered in Chevelles over the years. The Powerglide 2-speed automatic was available from 1964 through 1973. A 3-speed Turbo Hydra-Matic 350, aka TH350 (along with some later variants), was first introduced in the 1969 model year and was available through 1977. A beefier Turbo Hydra-Matic 400, aka TH400 (and variants), was first used in Chevelles in 1967 and was available only with the 396-, 402-, and 454-ci engines. Variants of the TH400 were used in post-1973 model years behind a variety of engines.
Several manual 3-speed transmissions saw their way into Chevelles. Various light-duty and heavy-duty manual 3-speeds and a manual 3-speed overdrive saw duty with all Chevelle engines except the 396, 402, and 454. Surprising to some, the heavy-duty 3-speed was the standard transmission used in the SS396 series of 1967 through 1968 and the SS396 Equipment Chevelles in 1969. Various gear ratios for first, second, and reverse were used depending on the year and engine it was installed with.
The 1969 SS Equipment Malibu convertible in Hugger Orange was one of two special SS Equipment option only colors. The special SS-only colors Hugger Orange and Daytona Yellow were still a $42.15 option. (Photo Courtesy Jacquie Benthin)
Several manual 4-speed transmissions were offered as options throughout the years. What is commonly called a wide-ratio or wide-range 4-speed was first offered in 1964 and also used in 1965. The Regular Production Order (RPO) code for this transmission is M20. This RPO code became important in mid-1966.
The 1964 and 1965 versions of the Muncie M20 differed from later versions in several ways; most apparent was the gear ratios. The 1964 and 1965 Muncie M20 had a first-gear ratio of 2.56:1, a second-gear ratio of 1.91:1, a third-gear ratio of 1.48:1, a fourth-gear of 1.00:1, and reverse 2.64:1. The 1966 and later Muncie M20 4-speed transmissions changed the ratios to 2.52:1 for first, 1.88:1 for second, 1.46:1 for third; fourth remained at 1.00:1; and reverse changed to 2.59:1.
Sometime around February or March 1966, Chevelles were introduced to a second wide-ratio 4-speed transmission. A cast-iron case unit was built at the Saginaw, Michigan, transmission plant and typically used behind engines of 300 hp or less. This Saginaw 4-speed carried the same RPO number, M20. When a dealer or individual buyer ordered a Chevelle with a 4-speed, the dealer checked the “4-speed wide-range” box (or similar verbiage). When the order reached the assembly plant, the decision was made as to which M20 the car would actually receive, the aluminum Muncie or the cast-iron Saginaw. The gear ratios in the Saginaw 4-speed manual transmissions varied depending on the engine being installed.
All automatic and manual transmissions were supposed to have a VIN derivative stamped on them as well, but that has been shown to not be the case and many Chevelle transmissions have been documented without a VIN derivative. Typically the engine and transmission were stamped at the time the two were mated so the fonts of the characters were the same size and type. These stamps differ from the Flint or Tonawanda engine assembly plant date and suffix code stamps in both size and font style because they were stamped at different facilities.
Buick, Oldsmobile, and Pontiac divisions of General Motors had their own A-Body platform cars. Buick had the Skylark nameplate, Oldsmobile had the Cutlass, and Pontiac had the LeMans. Buick, Oldsmobile, and Pontiac also had various trim levels and specialty models over the years with the top performance dogs being the Buick GS, Oldsmobile 4-4-2, and Pontiac GTO.
Each General Motors division had its own design and engineering departments and there was very little commonality between them; different engine designs, interior designs, etc. Many transmissions were essentially the same, such as the Muncie 4-speed and Turbo Hydra-Matic 400.
Although there were some variations in paint colors offered, many times the same paint color simply had a different sales name. For example, the 1970 Chevelle white was called Classic White. Buick called this same color Glacier White; to Oldsmobile buyers it was Porcelain White; and Pontiac buyers know it as Polar White. Same color, same mixing formula, just different names.
This “eyebrow” trim piece was discontinued in February 1970. The reason isn’t known but it’s generally accepted to have been unnecessary and was discontinued to save cost. It was not unique to SS Malibus but came on all 1970 Chevelles.
Each GM division offered various options not used by their counterparts such as the W-30 cold-air package used by Oldsmobile, the hood-mounted tachometer and rear spoiler found on some GTOs, and Stage I and Stage II engine options found on the Buick Grand Sport.
GM