Small-Block Chevy V-8 Through the Years: Highlights of a Legend
It’s not unreasonable to say the Chevrolet small-block V-8 changed the face of automotive engine history. Innovative and technologically advanced when it debuted in 1955, it greatly influenced future V-8 engine designs, both inside General Motors and among the competition. Enthusiasts embraced it and an entire performance aftermarket sprang up around it. Over the years, variations of the small-block V-8 have been used in race cars, off-road trucks, boats, and even custom motorcycles. It can also be found under the hood of everything from classic Ford hot rods to radical Jeep conversions.
“The small-block Chevy is unquestionably the dominant domestic engine both in terms of sheer numbers and also in terms of longevity,” said Jeff Smith, senior technical editor for Car Craft Magazine. He cites the engine’s interchangeability as one of the biggest reasons for its popularity. “It’s possible to swap a set of heads from a 1990 Vortec truck engine onto the original ’55 265. I doubt there’s an engine ever built (perhaps the VW) that you could swap parts from engines 45 years apart.”
“The aftermarket loves engines like the SBC because they knew that if they invested in a decent design like a good flowing cylinder head or a well-designed performance camshaft, that the design would have a decade or more worth of longevity,” Smith added.
Bill Tichenor, director of marketing for Holley Performance Products, echoes Smith’s sentiments. “It is not unreasonable to say Holley has sold more speed parts for small-block Chevys than all other engines combined. There are great engines from Ford, Chrysler, and others, but the proliferation of cores and affordability of making power with a small-block Chevy made it rise to the top. They certainly have been the engine of choice for street rodding, Chevy muscle cars and trucks, circle track racing, and a lot of drag car, too.”
Interestingly, the small-block Chevy was not the first V-8 in the brand’s history. From 1917-19, some 3,000 cars were equipped with the little-known Chevy Series D V-8. The 288-cubic-inch (4.7-liter) V-8 had a 4.75:1 compression ratio and produced 55 horsepower at 2,700 rpm. The Series D was the first overhead valve V-8 and featured an exposed valvetrain, nickel-plated valve covers, and an aluminum water-cooled intake manifold.
Three-and-a-half decades after that initial effort, the small-block Chevy was born. Developed as a replacement for Chevrolet’s “stove-bolt” six-cylinder engine, the 265-cubic-inch (4.3-liter) “Turbo-Fire” engine arrived in 1955 as an option for the Bel Air and Corvette. Its compact, lightweight design featured 4.4-inch bore spacing and a thin wall casting to reduce weight. An internal oiling system, and the potential to bore and stroke it far beyond the factory limit of 400 cubic inches (Gen I engines), contributed to its long-term success.
We’ve put together the following list of 10 of the most impressive small-block Chevy V-8s in the brand’s history. Enjoy the V-8 power trip.
265 Turbo-Fire V-8
The 265 arrived on the scene with a 3.75-inch bore and 3.00-inch stroke (95.2 – 76.2 mm). It made 162 horsepower and 257 lb-ft in base form with a two-barrel carburetor. An optional Power Pack added a four-barrel carburetor (and other modifications) taking power up to 180 horsepower and an even 260 lb-ft of torque. When fitted to the Corvette, the 265 made 195 horsepower through a dual exhaust system. Later in the year Chevrolet added a Super Power Pack option to the Bel Air, taking it to Corvette power levels.
In 1956, the 265 in the Corvette was available in three more powerful flavors: 210 horsepower with a single four-barrel carburetor, 225 horsepower with “dual quads,” and 240 horsepower with the dual four-barrel carburetors and a high-lift camshaft. Its compact size was made possible by consolidating accessories. According to GM, it used a one-piece intake manifold that combined the water outlet, exhaust heat riser, distributor mounting, oil filler, and valley cover into a single casting.
283 Turbo-Fire V-8
The small-block Chevy was blessed with more displacement in its third year (the 162 horsepower 265 was still the base engine). A larger 3.875-inch bore brought the “Mighty Mouse” up to 283 cubic inches (4.6 liters). Early 283s used 265 block castings, but thin cylinder walls contributed to overheating. The issue was caught early on and subsequent 283 engine blocks were specifically cast to prevent the problem.
The 283, dubbed Super Turbo-Fire, came with a choice of a carburetion or mechanical fuel injection. It made 185 horsepower with an 8.5:1 compression ratio and two-barrel carburetor; 220 horsepower with 9.5:1 compression and four-barrel carburetor; and 245 or 270 horsepower when fitted with dual four-barrel carburetors and the higher compression ratio.
Models equipped with the Rochester Ram-Jet fuel injection system made 250 horsepower. The most powerful engine of the lot was the 283-hp fuel-injected Super Ram-Jet with its 10.5:1 compression ratio, helping it achieve the coveted one horsepower per cubic inch status. In Motor Trend testing at the time, a 1957 Corvette fitted with the Super Ram-Jet reached a top speed of 132 mph at the General Motors Proving Grounds outside of Milford, Michigan.
By 1962, a 170-horsepower version of the 283 became Chevy’s base V-8, but optional small-block V-8s received a full 4.00-inch bore and a longer stroke at 3.25 inches for a total displacement of 327 cubic inches. The optional 327 was available with 250, 300, or 340 horsepower, depending on the four-barrel carburetor and compression ratio. The Corvette was still available with mechanical fuel injection, which pumped out 360 horsepower with an 11.25:1 compression ratio.
The 327-cubic-inch small-block reached its peak power rating in 1965: 365 horsepower with a four-barrel Holley carburetor or 375 (1.15 hp/cu-in) with the Rochester Ram-Jet fuel injection system. By mid-1965, the 327 played second fiddle to the 396-cubic-inch big block that debuted in the Corvette. It soldiered on as the base engine with a choice of 300 or 350 horsepower. It remained as a step up from the base 283s (and later 307s) in passenger cars and the base engine in the Corvette until the 350 (first seen in the 1967 Camaro) was introduced into America’s sports car in 1969.
The Camaro was Chevy’s response to the Ford Mustang. Besides defending GM’s entry-level brand, the Camaro introduced two small-block displacement landmarks. First up was the 302-cubic-inch engine designed for SCCA Trans Am competition. The 302 was created by combining the 327’s engine block casting (4.00-inch bore) with the 283’s crankshaft (3.00-inch stroke). This engine was built for competition and featured plenty of race-car kit, including an 11:1 compression ratio; four bolt main caps; a solid-lifter camshaft and solid valve lifters; high-rise intake manifold topped with an 800 CFM Holley four-barrel carburetor; high-capacity oil pump and baffled oil pan. It exhaled through a 2.25-inch dual exhaust system. The engine was finished with a chrome-plated air cleaner, rocker covers, filler tube, and cap.
Camaro owners who opted for the Z/28 package were rewarded with a 302 pumping out 290 horsepower at 5,800 rpm and 290 lb-ft of torque at 4,200 rpm. Many believe the horsepower rating was conservative. Z/28 owners found a box with tubular headers in the trunk. With the headers installed, a proper carburetor main-jet, and ignition-timing tuning it produced around 376 horsepower. Race engines with dual quads made as much as 465 horsepower. During its three year production run, more than 19,000 Camaro buyers opted for the Z/28, and with good reason.
The 1967 Camaro also brought the world the first 350-cubic-inch small-block Chevy V-8. This engine would eventually be used in passenger cars and trucks in nearly every imaginable level of tune. Like the 302, it was based on the 327 block, but the 350 had an all-new crankshaft with a 3.48-inch stroke. The first version, dubbed the L-48, produced 295 horsepower and 380 lb-ft of torque. The 350 became available in the Nova in 1968 and in its third year it was optional across the Chevrolet passenger car line. It replaced the 327 as the base engine in the Corvette in 1969. Power fluctuated during the 1970s fuel crisis, and many versions of the 350 emerged. At its lowest point the 350 was rated at a mere 145 horsepower (net).
But it didn’t take long for the small-block Chevy to regain its reputation as a powerhouse. The L-48 and ZQ3 both hit the 300 horsepower mark. Two other versions surpassed those numbers: the 350 horsepower (net) L-46, optional in the 1969 Corvette, and the LT-1 in 1970. The LT-1 came ready to battle with solid lifters, 11:1 compression, high-po camshaft, and a 780 CFM Holley four-barrel carburetor that sent fuel and air through an aluminum intake manifold. Exhaust gasses exited the combustion chamber through ramhorn manifolds and high-flow exhaust. In 1970, the LT-1 cranked out 370 horsepower (gross) and was available in the Corvette ZR-1 and Camaro Z28. Just two years later the power level dropped to 255 horsepower (net).
It took nearly 15 years before the Chevy 350 got an injection of power. The L98 began the slow process. GM blessed the L98 350 with an all-new tuned-port fuel injection system forever known by Chevy fans as the TPI and recognized by its elephant leg runners. Although it was only rated at 230 horsepower, it was a step up from the 205 horsepower L83 from the year prior. By 1991, power reached 245 horsepower in the Camaro and Pontiac Firebird and 250 horsepower and 345 lb-ft of torque in the Corvette.
The largest version of the Generation I small-block was the 400 (6.6 liter). It was the only engine available with both the 4.125-inch bore and the 3.75-inch stroke crankshaft. It debuted in 1970 and was produced for 10 years. It featured Siamesed cylinders for greater strength, with the large bore and a larger 2.65 inch rod journal. Early models produced 265 horsepower with a two-barrel carburetor. A four-barrel carburetor option became available in 1974. In its darkest hour it only made 145 horsepower. Regardless of horsepower rating, the 400 was a torque monster. The engine was available in full-size A-body and midsize B-body Chevy passenger cars until the end of the 1976 model year. It soldiered on a few more years in full-size pickups.
It didn’t take long for hot rodders to put the 400’s 3.75-inch-stroke crankshaft in a 350 engine block, creating the 383 stroker. Water jackets in between all cylinders in the 350 engine block resisted overheating, unlike the 400 block, which didn’t have that cooling advantage. Although the 383 was never offered as a factory option, this configuration’s popularity prompted GM to offer a 383 crate motor in its performance catalog.
The Corvette has always been a test bed for Chevrolet’s latest technologies—and the 1992 model with the Generation II LT small-block was no different. While many parts were interchangeable between Gen I and Gen II engines, the LT used a new block and head design with “reverse flow” cooling system that sent coolant through the cylinder heads first before flowing down through the engine block. The heads and combustion chamber stayed consistently cooler, allowing higher compression and more spark advance for increased power. The water pump, intake manifold, and dampener/pulley system were all unique to the Gen II small-block.
However, GM wisely kept the engine mounts and bell housing bolt pattern the same so hot rodders could transplant the new engine into an older chassis.
The 1992 Corvette made 300 horsepower and 330 lb-ft of torque. The fourth-generation F-Body twins (Chevrolet Camaro and Pontiac Firebird) gained the LT1 for their 1993 redesign and were rated 275 horsepower and 325 lb-ft of torque. The engine was also available in the full-size B- and D-body GM vehicles. Most memorable is the 1994-1996 Chevrolet Impala SS with 260 horsepower and 330 lb-ft of torque. All engine blocks were iron, but Corvettes and F-body cars had aluminum heads. Full-size cars had iron heads. For 1996, Corvettes equipped with six-speed manual transmissions (including all Grand Sports) were powered by a limited run (6359 units) 330-horsepower LT4 engine with 340 lb-ft of torque. In 1997, the Chevrolet Camaro SLP/LT4 SS and Pontiac Firebird SLP/LT4 Firehawk were available with the LT4. Only 135 F-bodies were built with the LT4.
The LT1 used a speed density fuel management system with batch-fire fuel injection in its first two years. In 1994 it received a mass airflow sensor and sequential port injection. The engine control module (ECM) was also replaced with a more powerful control module (PCM). The 1994 Corvette received the new OBD II system for testing before the government mandated requirement began in 1996.
The new engine wasn’t without its faults. Early models were plagued by a small design flaw in the Opti-Spark distributor. Vacuum vents were added to the distributor to remove the moisture that affected its spark ability. Unfortunately, the water pumps leaked water and coolant into the vents, ruining the distributor. Although not as popular as the original small-block Chevy – or the later LS engine family – the LT1/LT4 still appeals to many enthusiasts.
“Perhaps the only hiccup in the SBC lineage was the LT1/LT4 variation with its reverse cooling and Opti-Spark ignition variables that made that engine less popular. And yet, it still commands interest despite its very short lineage,” said Smith.
GM’s Generation III engine first hit the scene in 1997 in the all-new C5 Corvette. The LS series engines had little in common with the first two generations of the small-block Chevy, but still used 4.4-inch bore spacing. Most truck versions of the Gen III engine family had an iron block and aluminum heads, but the performance engines had aluminum blocks with six-bolt main caps.
In the Corvette, the LS1 made 345 horsepower and 350 lb-ft of torque. It arrived in the F-body twins a year later making 305 horsepower in Z28 and Formula trim and 325 horsepower with the SS and Trans Am ram-air packages.
Gen III engines introduced coil-near-plug ignition in place of a distributor and redesigned heads for increased air flow and power. The LS1 had a smaller bore and longer stroke than the Gen I and Gen II 350/5.7-liter V-8s. The new engine used a 3.89-inch (99.0 mm) bore and a 3.62-inch (92 mm) stroke for a total displacement if 345.7 cubic inches or 5.7 liters.
In 2001, the Corvette Z06 was introduced with a higher-performance 5.7-liter called the LS6. Power was bumped to 385 horsepower and 385 lb-ft of torque. The next year it received another bump in power to 405 horsepower and an even 400 lb-ft of torque. The LS6 was used in the Corvette Z06 until the C5 was replaced by the C6 in 2005. Cadillac used the LS6 in the first-generation CTS V from 2004-2005.
The LS6 was based on the LS1 engine, but had a stronger block; a redesigned intake manifold and larger MAF-sensor for better breathing; a “bigger” camshaft and higher compression ratio; and a revised oiling system for track use.
The Generation IV small-block Chevy V-8 hit the streets in 2005 and is based on the Generation III but was redesigned to utilize displacement on demand and variable valve timing technologies. The LS7 is the largest factory-installed small-block Chevy V-8 ever, displacing 427.8 cubic inches or just over 7.0 liters. It featured the same bore as the 1970s 400-cubic-inch engine of 4.125 inches (104.8 mm), but unlike the 400, the LS7 got a full 4.00-inch (102 mm) stroke crankshaft. The 7.0-liter small-block monster has a 7100 rpm redline and churns out an astonishing 505 horsepower and 470 lb-ft of torque — the most net horsepower of any naturally aspirated small-block in GM’s history.
Still based on the original 4.4-inch bore spacing, the LS7 uses pressed-in cylinder liners and forged steel bearing caps, forged titanium connecting rods, and hypereutectic pistons for strength. Intake valves are titanium and exhaust valves are sodium-filled. The hand-built LS7 is assembled at the General Motors Performance Build Center in Wixom, Michigan, and features a dry-sump oiling system to cope with high-lateral g’s experienced during track days and enthusiastic driving. In North America the engine comes factory-equipped in the 2006 to present Corvette Z06 or as a crate engine.
A serious highlight in the small-block V-8’s history would have to be the Generation IV LS9 engine: a 6.2-liter (376-cubic-inch) engine topped with an Eaton four-lobe Roots type 2300 TVS supercharger. The LS7 was considered for the base engine, but the smaller bore and thicker cylinder walls of the LS3 engine were required for durability under boost. Bore is 4.06 inches (103 mm) and stroke is 3.62 inches (92 mm). Power is rated at 638 horsepower at 6500 rpm and 604 lb-ft of torque at 3800 rpm — the most powerful factory-installed small-block Chevy ever. No surprise that the engine debuted in the most extreme sports car ever from GM: the 2009 C6 Chevrolet Corvette ZR1. In our testing the ZR1 went from 0-60 mph in 3.3 seconds and cleared the quarter mile in 11.2 seconds at 130.3 mph.
The LSA is a detuned version of the LS9 engine and debuted in the 2009 Cadillac CTS V. This version is still capable of a substantial 556 horsepower and 551 lb-ft of torque. It is the most powerful engine ever offered in a Cadillac up to that point, and was available in all three CTS body styles: the sensuous coupe, sedate sedan, wagon. This engine is capable of pushing the nearly 4353-pound wagon to 60 mph in 4.1 seconds and through the quarter mile in 12.5 seconds at 114.8 mph.
Gen V LT5
The C7 Corvette went out with a big, supercharged bang: the ZR1, powered by the 6.2-liter LT5. It’s a beastly thing, cranking out 755 horsepower courtesy of an Eaton supercharger. It’s based on the venerable LT4 engine, but there’s a host of new go-faster bits: a 95mm throttle body, port- and direct-injection, a stronger crankshaft, a new oiling system, and a 52 percent larger supercharger. Peak boost tops out at 13.96 psi near max rpm.
But unlike the LT4, there’s less propensity for heat-related issues thanks to four new heat exchangers and 41 percent more cooling airflow overall. All this power is good to rocket the ZR1 to a 3.2-second 0-60 time and an 11.2 second quarter mile in our testing. What a finale.
With nearly 25 years under its belt in truck and passenger car duty, the LS-series family has become widely available and affordable. The aftermarket has embraced it in much the same way it did the original small-block Chevy V-8.
“As the original small-block Chevy becomes harder to find in junkyards, we continue to see GM’s LS engine taking over where the original small-block left off,” said Tichenor. “LS engines are readily available and are even easier to make power with than the original. They are extremely reliable and smooth and now Holley is making speed parts for the LS just as we did for the traditional small-block Chevy. Looks like here we go all over again!”
This article was originally published in 2011 and has been lightly edited and updated for context and clarity.
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