Plymouth Belvedere 426 Max Wedge

Plymouth Belvedere 426 Max Wedge

The Plymouth Belvedere 426 Max Wedge represents one of the most important chapters in American drag racing history. Before the legendary 426 Hemi arrived in 1964, it was the Max Wedge engine that carried Chrysler's banner on the nation's drag strips, and the lightweight Belvedere was its most effective delivery vehicle.

The 'Max Wedge' designation referred to the maximum performance version of Chrysler's wedge-head B-series engine family. The 426 cubic inch displacement was achieved through a combination of the 413's bore with an increased stroke, creating an engine designed specifically for competition. The engine featured cross-ram intake manifolds with dual Carter AFB four-barrel carburetors, special exhaust manifolds with cast-in heat risers, and high-compression pistons.

Two versions of the Max Wedge were offered: the 'street' version with 11.0:1 compression producing 415 horsepower, and the race version with 13.5:1 compression rated at 425 horsepower. The higher-compression version was essentially a race engine that happened to be factory-installed, requiring aviation fuel or racing gasoline to avoid detonation.

Chrysler offered the Max Wedge in its lightest possible package: the Belvedere two-door sedan. By selecting the base-trim Belvedere rather than the more luxurious Savoy or Sport Fury, buyers could save several hundred pounds of weight, a critical advantage in competitive drag racing. Some factory race cars were further lightened with aluminum front fenders, hood, and bumper brackets.

The Max Wedge Belvedere was devastatingly effective on the drag strip. In 1962 and 1963, Max Wedge Plymouths and Dodges dominated the NHRA Super Stock classes, with drivers like Tom Grove and Al Eckstrand setting records at national events. The combination of massive power and relatively light weight produced quarter-mile times in the low 12-second range, extraordinary for factory-stock competition.

The cross-ram intake manifold was one of the Max Wedge's most distinctive features. By running the intake runners from each carburetor to the opposite cylinder bank, the design used the velocity of the intake charge to improve volumetric efficiency at high RPM. The long runners created a pronounced torque peak that made the engine feel explosively powerful in its operating range.

The Max Wedge's competition career was brief but brilliant. By 1964, Chrysler had developed the legendary 426 Hemi, which superseded the Max Wedge as the company's ultimate performance engine. But the Max Wedge had served its purpose magnificently, establishing Chrysler as a dominant force in organized drag racing and creating a heritage of performance that would define the Mopar brand for decades.

Today, genuine Max Wedge Belvederes are among the most valuable and sought-after Mopar muscle cars. Their racing provenance, limited production numbers, and historical significance as the predecessors to the 426 Hemi have elevated them to the highest echelon of collectible American performance cars.