The 1964 Pontiac Tempest is a classic American muscle car known for its performance and versatility. Understanding the rear axle and its gear ratios is crucial for maintenance, restoration, and performance upgrades. This guide delves into the rear axle specifications of the 1964 Pontiac Tempest, providing detailed information on gear ratios based on engine and transmission configurations. Whether you’re looking to identify your current setup or planning a modification, this breakdown will offer valuable insights.
1964 Pontiac Tempest Rear Axle Ratios: Engine and Transmission Specifics
The 1964 Pontiac Tempest offered a range of engine and transmission choices, each influencing the factory-installed rear axle ratio. Here’s a detailed look at the standard and optional ratios:
215 Inline 6-Cylinder Engine
For models equipped with the 215 cubic inch inline 6-cylinder engine, the rear axle ratios varied depending on the transmission:
- 3-Speed & 4-Speed Manual Transmissions: These models typically came with a 3.08 ratio rear differential. This ratio provided a balance of acceleration and fuel economy for everyday driving.
- Automatic Transmission: Tempests with the automatic transmission and the 215 inline-six were equipped with a 2.56 ratio rear differential as standard. For those seeking slightly different performance characteristics, optional ratios of 2.78 and 2.93 were also available.
326 V8 Engine
The more powerful 326 cubic inch V8 engine offered in the 1964 Pontiac Tempest also had distinct rear axle ratios based on carburetor and transmission type:
326 2-bbl V8 Engine
- 3-Speed & 4-Speed Manual Transmissions: Vehicles with the 2-barrel carburetor 326 V8 and manual transmissions were fitted with a 3.23 ratio rear differential. A 3.08 ratio was available as an option for drivers prioritizing highway cruising.
- Automatic Transmission: The automatic versions of the 326 2-bbl V8 Tempest used a 2.56 ratio rear differential as standard. Similar to the inline-six models, a 2.93 ratio was offered as an optional upgrade.
326 4-bbl V8 Engine
- 3-Speed & 4-Speed Manual Transmissions: For the high-performance 4-barrel carburetor 326 V8, manual transmission models boasted a 3.36 ratio rear differential. A range of performance-oriented optional ratios were also available, including 3.79, 3.90, and 4.30. These higher ratios were designed to maximize acceleration.
- Automatic Transmission: Tempests equipped with the 4-bbl 326 V8 and automatic transmission came standard with a 3.23 ratio rear differential. The same performance options as the manual versions were offered: 3.79, 3.90, and 4.30 ratios.
Pontiac A-Body vs. Buick A-Body Rear Differentials: Key Differences
For those considering parts swapping or replacements, it’s useful to know about the subtle differences between Pontiac and Buick A-Body rear differentials of this era. Visually, the primary distinction lies in the Pontiac differential having an additional web on each side. This design element was intended to enhance the strength and rigidity of the Pontiac differential housing.
Despite this external difference, the internal components are generally interchangeable between 1964-1966 A-Body rear differentials within the same gear ratio group. Furthermore, components like the upper control arm bushings for the 326 V8 Pontiacs and the 1965 Buick Skylark are reported to be identical. While confirmation is needed for the 215 inline 6-cylinder rear differential, it is also believed to share the same compatibility. Crucially, the hub-to-hub lengths are identical between these A-Body differentials.
Conclusion
Understanding the rear axle specifications of the 1964 Pontiac Tempest is essential for anyone working on or appreciating these classic vehicles. From gear ratios tailored to engine and transmission types to the subtle differences in A-Body differentials, this information provides a foundation for informed maintenance, restoration, and performance enhancements. Whether you’re diagnosing an existing Tempest or planning a modification, knowing these details ensures compatibility and optimal performance.
