Chrysler Slant-6

The Slant-6 is one of Chrysler's two best known automobile engines, along with the Hemi V8. The engine is an inline-6 piston engine specifically designed such that the cylinders are inclined at a 30-degree angle from vertical. The 30° inclination of the Slant-6 gave a lower height overall engine package, which enabled vehicle stylists to lower hoodlines, and also made room for the water pump to be mounted with a significant lateral offset, significantly shortening the engine's overall length. In addition, the slanted cylinder block provided ample space under the hood for intake and exhaust manifolds with runners of longer and more nearly equal length compared to the "rake" or "log" style manifolds found on other inline engines. These manifolds give a more even cylinder-to-cylinder fuel distribution and are less restrictive for better airflow through the engine.

The engine was introduced in two sizes in 1960: The 170 cubic-inch (2.8 L) "LG" (Low-G, referring to the relatively short engine block casting and crankshaft stroke) in the Valiant, and the 225 CID (3.7 L) "RG" (Raised-G, referring to the relatively tall engine block casting and crankshaft stroke) in full-size Plymouth and Dodge Dart models. In 1960, the engine was referred to by Plymouth division as the "30-D Economy Six" engine, the "30-D" referring to the 30° cylinder block angle.

The G-engine gained an enviable reputation for reliability and nearly unstoppable durability. The basic engine design incorporates much heavy-duty engineering, in part because the engine was designed from the start to be made of either iron or aluminum: The block is of a deep-skirt design, with the crankshaft axis well above the oil pan rails for structural rigidity. Although only four main bearings are used, they are of the same dimensions as those in the Hemi. Very efficient cooling and lubrication systems, a favorable rod ratio, and an extremely strong forged steel crankshaft (on engines made through mid-1976) all contributed to the engine's apparent indestructibility. In addition, the G-engine also provided better performance than most of its competition in the 1960s and 1970s.

The G-engine was offered in various configurations in the North American market until 1983 in cars, and 1987 in trucks.