The 1964 Pontiac Tempest is a classic American muscle car that offered a range of engine and transmission options, each influencing the rear axle ratio. Understanding these specifications is crucial for restoration, performance upgrades, or simply maintaining your vintage vehicle.
For the 1964 Pontiac Tempest, engine choices included a 215 cubic inch inline 6-cylinder and a more powerful 326 cubic inch V8. The V8 was further available with either a 2-barrel or 4-barrel carburetor, affecting performance and, consequently, rear axle ratios.
Let’s delve into the rear end ratios offered for the 1964 Pontiac Tempest based on engine and transmission configurations:
1964 Pontiac Tempest Rear Axle Ratios Based on Engine and Transmission:
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215 Inline 6-Cylinder Engine:
- 3-Speed & 4-Speed Manual Transmissions: A 3.08 rear axle ratio was standard. This provided a balance of acceleration and fuel economy for manual transmission models.
- Automatic Transmission: A 2.56 rear axle ratio was standard, geared towards smoother cruising and potentially better fuel efficiency at highway speeds. Optional ratios of 2.78 and 2.93 were also available for those seeking a slight variation.
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326 2-Barrel V8 Engine:
- 3-Speed & 4-Speed Manual Transmissions: A 3.23 rear axle ratio was the standard configuration. A 3.08 ratio was available as an option, possibly for drivers prioritizing fuel economy over quicker acceleration.
- Automatic Transmission: Similar to the 6-cylinder automatic, a 2.56 rear axle ratio was standard. A 2.93 ratio was offered as an option, giving a bit more responsiveness.
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326 4-Barrel V8 Engine:
- 3-Speed & 4-Speed Manual Transmissions: Performance-oriented ratios started to appear here. A 3.36 rear axle ratio was standard, enhancing acceleration. Optional ratios included 3.79, 3.90, and even a 4.30 for serious performance enthusiasts wanting maximum off-the-line speed.
- Automatic Transmission: A 3.23 rear axle ratio was standard for the 4-barrel V8 automatic, again reflecting a performance bias. The same optional performance ratios of 3.79, 3.90, and 4.30 were also available.
Pontiac A-Body vs. Buick A-Body Rear Differentials: Similarities and Differences
For those considering parts swapping or understanding the chassis design, it’s worth noting the relationship between Pontiac and Buick A-body rear differentials of this era. Visually, the Pontiac differential is reported to have an additional web on each side of the differential housing, potentially for added strength. However, internally, components are generally interchangeable between 1964-1966 models, especially within the same axle ratio.
Furthermore, the upper control arm bushings for at least the 326 V8 Pontiacs and the 1965 Buick Skylark are considered identical. While confirmation is needed for the 215 inline-6 cylinder models, it’s believed that rear differentials are also interchangeable in terms of overall dimensions and mounting points. Length-wise (hub-to-hub), they are also considered identical.
Conclusion
When working on a 1964 Pontiac Tempest, especially concerning the rear axle, understanding the original specifications based on engine and transmission is key. While sharing similarities with Buick A-body platforms, verifying specific component compatibility is always recommended for a successful and safe restoration or modification. This guide provides a starting point for navigating the rear end options of the classic 1964 Pontiac Tempest.
