Chrysler 340 Six Pack?! A High-Performance Marvel
The 1970 Chrysler 340 Six Pack engine wasn’t just another motor—it was a masterpiece born from the mind of Tom Hoover, known as the “father of the Hemi.” Designed specifically for the SCCA Trans-Am Racing Series, this engine powered iconic cars like the AAR Cuda and Dodge Challenger T/A. Straight from the factory, it was a race-ready powerhouse with untapped potential to dominate the track.
Built to Perform
Reinforced Block: The high-nickel engine block was stress-relieved and featured thicker webbing, allowing the installation of four-bolt main caps on the second, third, and fourth journals for increased strength.
Advanced Cylinder Heads: High-performance “J” casting cylinder heads housed oversized valves and an offset pushrod hole design, leaving room for aggressive intake porting.
Forged Internals: A forged crankshaft, heavy-duty connecting rods, and high-performance pistons were designed to handle the demands of racing.
Optimized Combustion: The engine boasted a 10.5:1 compression ratio, an aggressive 276/284 duration camshaft, and a dual-row timing chain, ensuring precision and power.
Six Pack Induction Magic
At the heart of the 340 Six Pack was its unforgettable carburetion system. Three Holley two-barrel carbs sat atop a factory Edelbrock intake manifold, with a 375 cfm center carb handling primary duties. At higher throttle openings, two 500 cfm outer carbs kicked in, delivering a thunderous 1375 cfm of airflow and an induction roar that echoed across the track.
Factory Numbers and Real-World Power
Officially rated at 290 horsepower and 345 lb-ft of torque, the consensus among enthusiasts was that the Six Pack 340 actually produced closer to 330 horsepower. Performance numbers supported this claim, with quarter-mile times of 14.4 seconds and a 0-to-60 mph sprint in just 5.8 seconds for a 3500-pound car.
Trans-Am Racing Legacy
In race trim, the 340 was de-stroked to meet Trans-Am’s 305 cubic-inch displacement limit. Throughout its racing evolution, it was rumored to produce anywhere between 460 and 500 horsepower, solidifying its place as a fierce competitor on the track.
The 340 Six Pack engine is remembered not just for its performance but for its clever engineering and unmistakable sound. It remains a testament to Chrysler’s ability to build engines that were as durable as they were powerful.
