Chrysler Slant-6 Vs. AMC/Jeep Inline-6: Which Is The Better Engine?

The first straight-six internal combustion engine design, produced by Spyker in 1903, led to widespread usage of similar designs over the following years. While V8 power would eventually dominate the muscle car era, many popular cars of the time, including the first Ford Mustang offering, were powered by straight-six-cylinder engine layouts.

Between the Chrysler Slant-6 and AMC Inline-6 straight-six-cylinder engines, the Slant-6 was the first to market, with a 170 cubic-inch variant available in the 1960 Plymouth Valiant. The first AMC 3.8-liter Inline-6 Typhoon roared to life in the 1964 AMC Rambler Classic.

Power ratings for these early engines pale in comparison to upcoming V8 powerplants, but what these engines lacked in power, they made up for with consistent reliability and smooth operation. Throughout the first half of the 1960s, the Slant-6 produced 101 horsepower and 155 lb-ft of torque. For comparison, AMC's 1964 Inline-6 Typhoon produced 145 horsepower and 215 lb-ft of torque.

Which engine is better?

During their production lifespans, both engines evolved. In its prime, from 1961 to 1962, the 225 cubic-inch Slant-6 peaked at 196 horsepower, while the 170 cubic-inch version increased from its original 101 to 148 horsepower when equipped with the Hyper Pak system option. The AMC Typhoon Inline-6 eventually became Jeep's 4.0-liter workhorse, which topped out at 190 horsepower and 235 lb-ft of torque in 1991 Wranglers and 1993 Cherokees until the end of its production in 2006.

The final 225 cubic inch Slant-6 production engines were found in larger Chrysler, Dodge, and Plymouth cars, often used in taxicab fleets and as police cars, until 1984, and Dodge pickup trucks until 1987. These later model engines suffered from electronically controlled carburetors and computerized engine control modules that made troubleshooting problems chaotic. Many theorize the engine's electronics issues led to its removal from Chrysler's engine offerings.

On the contrary, Jeep's 4.0-liter Inline-6 powered some of the company's most legendary and iconic off-road capable vehicles, such as Wrangler and Cherokee models, until it was replaced in 2007 by the 3.8-liter V6. The 2007 Wrangler with a 3.8-liter V6 generated 202 horsepower and 237 lb-ft of torque.

While the Chrysler Slant-6 performed well in its early years, it's no match for the AMC/Jeep Inline-6. The AMC/Jeep Inline-6's longevity and reputation as a rugged, reliable powerplant for off-road vehicles puts it ahead of Chrysler's troublesome Slant-6.