There are those out there who remember when the Chevy small-block was a brand-new entity in the automotive world. And there are also two or three generations of enthusiasts who have never known a time without the ubiquitous small-block V-8.
The Chevy small-block wasn’t called the small-block until the big-block was introduced for 1965. But the engine originally known as the Chevy V-8 got its start in the years following World War II. GM had weathered the war years pretty well, as war production boosted research and development processes. But when it came time to start building civilian passenger cars again, Chevy was one of the General’s companies that were still saddled with antiquated products – with the ancient Stovebolt inline-six leading the way. .
With eight-cylinder engines available in Fords for years, Chevy engineers began work on their own V-8 and they were well into the project when Chief Engineer Ed Cole came aboard from Cadillac. He had overseen the development of Cadillac’s overhead-valve V-8 engine and injected a does of needed perspective on the Chevy project.
Innovative product and process
When introduced in the all-new ’55 Chevy lineup, the new V-8 engine was smaller, lighter and more powerful than the Stovebolt six. It also represented a better way of building engines for GM.
The new small-block was designed with components and procedures that seem commonplace today, but were state-of-the-art half a century ago, including:
• Lightweight stamped-steel rocker arms that allowed a much higher rpm range.
• Hollow pushrods that carried oil to the cylinder heads.
• Single-piece intake manifold, which combined the water outlet, exhaust heat riser, distributor mount and valley cover.
• Internal lubrication, which eliminated the need for external oil lines and greatly reduced the chance of leaks – a breakthrough feature not found on other low-price car lines.
• Compact overall size required less iron in its manufacture, which, in turn, required less coolant during operation.
The new engine’s 4.400-inch bore centers became a symbol of the small-block’s compact performance. In fact, it was the dimension around which the all-new Gen III small-block was designed in 1997 and still uses in today’s Gen IV LS2 and LS7 engines.
With 3.75-inch bores and a 3.00-inch stroke, the first small-block displaced just 265 cubic inches (4.35 liters). Drawing its breath through a two-barrel carburetor, the base version produced 162 horsepower (gross). With a four-barrel, the engine was rated at 195 (gross) in the Corvette.
Interestingly, it was probably the addition of the new V-8, which saved the Corvette from cancellation after just a couple of years on the market. The original ’53 Vette had a “Blue Flame” insignia on the rocker cover; it was just another name for “old Stovebolt.” The new V-8 transformed the Corvette into a real sports car.
After its introduction, the small-block began a journey on unending technical evolution. Displacement grew, induction systems varied and even mechanical fuel injection was introduced in the late 1950s. A 327-cubic-inch version was hailed as the perfect V-8 until the 350 showed up at the end of the 1960s.
Of course, it was the 350 that made the Chevy small-block the yardstick against which other V-8 engines would be measured for the next 35 years. Indeed, the 350 has become the common link between millions of enthusiasts not only in the United States, but also around the world.
Dark days and better times
Through the years, the original-design Chevy small-block (not including the Gen III version introduced in ’97) grew to a maximum of 400 cubic inches. It also shrank considerably. In fact, GM’s 90-degree V-6, which has been used most recently as the Vortec 4.3-liter V-6, is just a small-block V-8 with two fewer cylinders.
As the tumultuous ’70s progressed, the small-block’s performance suffered, along with the rest of the auto industry. A 262-cubic-inch version was introduced in 1975 and rated at just 110 horsepower – making it smaller and considerably less powerful than the original ’55 version.
As the ’70s gave way to the 1980s, the small-block began its climb back up the technology and performance ladder. This was helped in no small part to its being selected as GM’s “corporate” V-8. It was a decision that still doesn’t sit well with dyed-in-the-wool Pontiac, Olds and Buick enthusiasts.
Engineers finally got the fuel injection formula right in 1985, with the introduction of Tuned Port Injection (TPI) on the Corvette and IROC Camaro Z28. This electronically controlled port fuel injection system was definitely advanced in its day and served as the basic blueprint for the fuel-injected engine used on most passenger cars and light-duty trucks to this day.
In 1986, the first revamp of the basic small-block design was introduced. It featured a revised block that was modified to accept an improved one-piece crankshaft seal. It also enabled the engine to accept aluminum heads, which quickly debuted on the Corvette. Their center-style valve cover bolts easily identify these later-style small-blocks.
In the 1990s, the Gen II small-block was introduced as the LT1. It featured new, low-friction internal components and reverse-flow cooling to enable the most powerful small-blocks since the heyday of the muscle car era. Some Gen II features, including the low profile, high-flow, intake manifold previewed technology that would be incorporated into the all-new Gen III.
The Gen III small-block was introduced as the LS1 5.7-liter engine in the 1997 Corvette. It shared nothing with the original engine, but 4.4-inch bore centers. Nevertheless, the Gen III and Gen IV engines share the same spirit of compact performance and design simplicity.
But while not in production vehicles, there are plenty of original-design small-blocks still to be found. GM Performance Parts offers a half-dozen crate engines based on the Gen I/Gen II design and there’s even a plant in Mexico that still produces Gen I-style engines with two-bolt main caps, a two-piece crank seal and pre-1986-style perimeter-hold-down valve covers.
GM’s Powertrain division estimates that when all the 90-degree V-6 versions, marine versions and countless other applications are factored in, something like 50 million small-blocks have been produced since 1955.
That’s a million small-blocks a year for the last half-century, ranking the compact V-8 as one of the top successes in the history of the auto industry.