389 Blocks (395-480 cu. In.)

Rotating Assemblies & Stroker Kits - 389 Blocks (395-480 cu. In.)

The Heart of an Era: Celebrating the Legendary Pontiac 389 V8

The roar of a Pontiac engine is synonymous with the golden age of American muscle. Among the pantheon of powerful Pontiac powerplants, few hold as significant a place as the 389 cubic-inch V8. Produced from 1959 through 1966, this engine was the backbone of Pontiac’s performance resurgence and, most famously, served as the original heart of the iconic GTO.1

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More About 389 Blocks (395-480 cu. In.)

 

Birth of a Legend

The Pontiac 389 arrived in 1959 as an evolution of the division’s overhead-valve V8 line, which began in 1955.2 For 1959, Pontiac engineers increased the stroke of the previous 370 CID engine from 3-9/16 inches to 3-3/4 inches, effectively creating the 389 CID (cubic inch displacement) engine.5

This robust, cast-iron block featured a 4.062 inch bore and the aforementioned 3.750 inch stroke, giving it a well-balanced architecture that proved excellent for both street cruising and high-performance applications.8 Throughout its run, the 389 was offered in a vast array of configurations, from economy versions making around 215 horsepower to high-output models topping out near 368 horsepower.9

The GTO's Foundation

The 389's most enduring legacy comes from its role in the creation of the muscle car. When John DeLorean and his team introduced the Gran Turismo Omologato (GTO) option package in 1964, they bolted a highly-tuned 389 V8 into the intermediate-sized Tempest.10

Early GTO 389s were available with a potent four-barrel carburetor setup producing 325 horsepower and 428 lb-ft of torque.11 For the enthusiast who demanded more, the legendary Tri-Power option—featuring three two-barrel Rochester carburetors—boosted output to an incredible 350 horsepower (some sources quote higher figures), cementing the GTO as an instant legend.12

Performance Capabilities and Legacy

The 389’s design allowed for significant factory and aftermarket development. High-performance versions often featured higher compression ratios (up to 10.5:1 on some 1959 "Super Duty" over-the-counter racing versions) and special camshafts.13

Even today, the Pontiac 389 remains a highly sought-after engine for restorations and performance builds, as championed by specialists like ButlerPerformance.com.

Modern Interpretations (Per Butler Performance Insights):

  • Versatile Platform: Enthusiasts and builders regularly utilize the sturdy 389 block for modern performance builds, often stroking it to displacements like 416 cubic inches.14
  • Power Potential: With modern components like aftermarket cylinder heads (such as Edelbrock D-port aluminum heads) and roller camshafts, contemporary 389 builds can reliably produce 400+ horsepower for daily drivers, with street/strip combinations pushing well past 600 horsepower.
  • Upgrades: Performance-focused rebuilds often focus on critical areas, such as upgrading to 4-bolt main caps for added rigidity in high-horsepower applications and utilizing forged components for durability.

The Pontiac 389 was more than just an engine; it was a statement. It helped define Pontiac’s performance image throughout the 1960s, paving the way for larger displacement engines like the 400 and the mighty 455 before the division's eventual discontinuation. For enthusiasts, the unmistakable sound and enduring performance of the 389 ensure its place in hot-rodding history remains secure.