Looking back on the mid-1950s, there’s no question that Chevrolet was winning – and winning big! The 1955 Bel Air was a massive hit, as were the brand’s 1956 and 1957 follow-ups. With the stalwart 265 Turbo Fire V8, the bowtie brigade brought affordable V8 power to the performance-hungry masses. For 1957, they upped the ante even more with the Turbo Fire 283 and optional Rochester mechanical fuel injection. By the numbers, Chevrolet sold 1.1 million cars in 1954. In 1955, with the debut of “The Hot One” and V8 power, the division moved 1.7 million cars. That’s a 60% yearly sales increase in a crowded market that averaged just eight million new car sales annually.

But times, they were a-changin’. The opulence of 1950s America began to influence every aspect of automotive design, and the mantra for every company was bigger is better. For many buyers, larger cars conveyed a more luxurious lifestyle, and Chevrolet leadership knew the division needed a bigger engine to power its increasingly large offerings. Enter Zora Arkus-Duntov and his high-performance engineering group.

Chevrolet W-Series Big Block V8

The Dawn Of Chevrolet’s Big-Block V8

Introduced in 1958, the now legendary Chevrolet Mark I big-block was, like its small-block predecessors, a clean sheet design. While enthusiasts commonly call the engine W-Block because of its offset valves and scalloped valve covers, the mill technically acquired its W branding in development. In reality, the W-Series design was branded “W” in a sequence of W, X, and Y engine setups Duntov’s high-performance engineering group tested. While options X and Y were enlarged versions of the Turbo Fire 265 small-block, the W-Block was an entirely new creation. Despite displacing 83 additional cubic inches, its exterior dimensions remained close to Chevy’s fabled small-blocks. That meant the mill could easily be interchanged on the production line, but that’s where the similarities ended. While the rev-happy small-blocks were built for power, the W-Series 348 was designed to be a torque monster.

1958 Chevrolet Impala Convertible

Initially hindered by GM’s smooth but slow Powerglide 2-speed, the 348 solidified its performance credentials once select dealers started pairing it with factory 4-speeds. For 1958, the base 348, equipped with a 4-barrel carburetor, was marketed as the 250 horsepower Turbo Thrust V8. Stepping up to the 280 horsepower Super Turbo Thrust V8 added three 2-barrel carburetors. The 305 horsepower Special Turbo Thrust V8 featured a bigger 4-barrel carburetor, and the top option Special Super Turbo Thrust V8 made 315 horsepower with the help of mechanical lifters and the same 6-pack setup as the Super Turbo Thrust. For 1959 and 1960, the Chevy Mark 1’s affordable V8 power climbed to 320, 335, 340, and 348. The immensely popular W-Block 348 would live just four years before being eclipsed in size and popularity by the fabled W-Block 409. 

She’s Real Fine!

The historical and cultural significance of the Chevrolet 409 simply cannot be understated. For starters, the engine, bolted into roughly 150 engine bays in 1961, helped debut Chevy’s now equally legendary Super Sport franchise. Secondly, many enthusiasts consider 409-equipped Chevys the first wave of American muscle, with packages like the infamous ‘Bisquick’ Biscaynes exemplifying the beauty of simple cars built around massive engines. And last but certainly not least, the 409 Impala SS was the subject of a smash hit created by the Beach Boys – one of the biggest and most influential bands of all time. The 409 debuted in 1961 with 360 horsepower and, by 1962, could be optioned up to 409 horsepower with the help of dual 4-barrel carburetors. By 1963, the top option dual-quad 409 was punching steep 11 to 1 compression into an epic 425 horsepower with the help of an aluminum intake, solid lifters, and a forged steel crank. 

1962 Chevrolet Biscayne

As renowned as the 409 has become, there is still one version of the W-Series big-block that’s both more exclusive and more impressive. Known internally as the Z11 option, this 427 cubic inch monster utilized cowl induction, dual-quad carburetion and an aluminum intake to twist colossal 13.5 to 1 compression into 430 horsepower and 575 lb./ft. of tire torching torque! According to sparse factory records, just over 50 Z11 427s were produced, with somewhere around 20 more ‘partial build’ engines banked for warranty repairs.

V8 Power For Work And Play

Like the small-block 400 we highlighted last month, much of the W-Series big-block’s performance chops come from the fact that it was engineered for maximum endurance in truck applications. The block is cast iron, with block decks that are angled at 74 degrees from crank centerline. Angled valves and a variety of angled pistons case wedge shaped combustion chambers that are inside the block itself. Actual truck applications feature a relief groove in the top of the cylinder walls to reduce compression and increase reliability. The 409 is simply a bored and stroked version of the 348, and the Z11 427 is a stroked version of the 409. And today, aftermarket suppliers offer stroker kits that take displacement far beyond 427 cubic inches.

Bringing affordable V8 power to the masses, the W-Series engines are legends among hardcore enthusiasts. But, like many things in Chevrolet’s orbit, they compete with other perhaps more spectacular moments and innovations. Chevy’s massively successful Mark IV big-blocks cast a big shadow, but it was the W-Series that kicked off the brand’s cachet as the number one source for American muscle!