Tuesday, November 29, 2011


The ubiquitous GM small block is approaching a rather significant milestone - the 100 millionth example will be produced sometime today:

WIXOM, Mich.– General Motors today will build its 100-millionth small-block engine – 56 years after the first production small block – representing an engineering legacy that continues to deliver greater performance and efficiency through advanced technology. 
Chevrolet introduced the small-block in 1955 and the production milestone comes in the same month the brand marked its 100th anniversary. The small-block engine has been used in GM vehicles around the world and is currently found in global Chevrolet, GMC and Cadillac vehicles, as well as Vauxhall in the United Kingdom and Holden in Australia.
“The small block is the engine that brought high-performance to the people,” said David Cole, founder and emeritus chairman of Center for Automotive Research – and whose father, the late Ed Cole, was the chief engineer at Chevrolet and oversaw development of the original small block engine. “There is an elegant simplicity in its design that made it instantly great when new enables it to thrive almost six decades later.” 
The milestone engine is a 638-horsepower supercharged LS9 small block – the power behind the 205-mph Corvette ZR1 – which is hand-built at GM’s Performance Build Center, northwest of Detroit. It represents the fourth generation of the small block and is the most powerful engine ever built by GM for a regular-production car. GM will preserve the engine as part of its historical collection. 
The small block has been adapted in almost innumerable ways throughout the auto industry and beyond. Updated versions of the original Gen I engine are still in production for marine and industrial applications, while “crate engine” versions offered by Chevrolet Performance are used by thousands of enthusiasts every year to build hot rods. The 4.3L V-6 used in some Chevrolet and GMC full-size trucks and vans is based on the small-block, too, but with two fewer cylinders. All of these versions contribute to the small block’s 100-million production milestone. 
“This tremendous achievement celebrates an engineering triumph that has reached around the globe and created an industrial icon,” said Sam Winegarden, executive director and group global functional leader - Engine Engineering. “And while the small-block’s enduring design has proven adaptable to meet performance, emissions and refinement challenges over the years, it has more importantly delivered them with greater efficiency.”

Current small blocks engines feature all-aluminum cylinder block and heads in car and many truck applications to help save weight and contribute to greater fuel economy. Many applications feature fuel-saving technologies such as Active Fuel Management – which shuts down four cylinders in certain light-load driving conditions – and camshaft phasing, which continuously alters valve timing to optimize performance, efficiency and emissions. 
The 430-horsepower (476 kW) LS3 version of the Gen-IV small-block helps the 2012 Corvette accelerate from 0 to 60 mph in about four seconds, run the quarter-mile in just over 12 seconds and achieve a top speed of more than 180 mph – all while achieving EPA-estimated highway fuel economy of 26 mpg. That compares favorably against many sports and performance cars.


In the beginning
GM didn’t invent the V-8 engine, but interpreted it in a way that made performance accessible to millions of new customers. It got its start in the years following World War II, after Chief Engineer Ed Cole transferred to Chevrolet from Cadillac, where he oversaw the development of its premium V-8 engine. 
Cole’s team retained the basic overhead valve design that was a staple of Chevrolet’s inline-six engine – affectionately called the Stovebolt. It was seen as one of the Chevrolet car line’s selling points, reinforcing a message of simplicity and reliability. Cole challenged his engineers to tighten the new engine package to make it more compact, less costly and easier to manufacture.
Upon its debut in the 1955 Chevy lineup, the new V-8 engine was physically smaller, 50 pounds lighter and more powerful than the Stovebolt six. It was not only a better engine for Chevrolet cars, it represented a better way of building engines, with a minimalist design that took advantage of streamlined production techniques. 
After only two years on the market, the small-block began a steady march upward in displacement, power and technological advancement. In 1957, a version equipped with mechanical fuel injection was introduced, dubbed Ramjet. The only other high-volume manufacturer to offer fuel injection at the time was Mercedes-Benz. 
Mechanical fuel injection was discontinued in the mid-Sixties, but the small-block debuted electronically controlled fuel injection in the 1980s and established a benchmark with the 1985 launch of Tuned Port Injection. This electronically controlled port fuel injection system was advanced in its day and its basic design is still used on most passenger cars and light-duty trucks more than 25 years later. 
The small-block’s 4.4-inch bore centers – the distance from the center of one cylinder to the next – would come to symbolize the compact, balanced performance of the small-block. It was the dimension around which the Gen III small-block was designed in 1997. In 2011, the small-block is in its fourth generation, powering Chevrolet’s full-size trucks, SUVs and vans, midsize trucks and the Camaro and Corvette performance cars. 
The first 4.3L (265 cu. in.) engine in 1955 produced up to 195 hp with an optional four-barrel carburetor. Today, the LS9 6.2L (376 cu. in.) supercharged small-block in the Corvette ZR1 is rated at 638 hp (476 kW), making it the most powerful engine ever installed in a regular-production Chevrolet or GM vehicle.


Of course, this is straight from a GM press release, but the info is legit!

Just because - an illustration by the automotive industry's finest cutaway illustrators - David Kimble. This is the 1967 302 V8 (Z28) for the Camaro. This particular motor had a four inch bore and a three inch stroke, which was considered at the time to be the perfect ratio for a high winding high horsepower V8, considered "over square." It was actually inspired by hot rodders who were taking 283 cranks and dropping them into 327 blocks. On a side note, the 283 block with a 327 crank made the 307. It was "undersquare" without the high winding horsepower capabilities, however, it's strength was high torque at comparable lower rpms. It made a fine truck motor and found it's way into who knows how many GM built pickups. It just didn't have the power that the later big blocks set up for high torque had - like the 366. Performance didn't always mean high horsepower for the engine line.

A typical tricked out small block. Check out the tuned headers with the shorty collectors stuck on some Edelbrock heads - this baby is set up to breath pretty free. It does have a fairly low profile intake manifold, but it's got some other high performance goodies like the Edelbrock fuel pump and a performance ignition system. It sure looks like it's based on GM's HEI setup - still has vacuum advance, for instance. I like the braided fuel line running from the pump to the unknown carb - if there was ever a weak spot in a small block it was the way GM routed their steel fuel lines - when they kept it close to the block and heads you'd have vapor lock in the summer sure as hell. That chrome coolant inlet on the top probably helped make another hp or three (snork!).

I am clearly a fan. Yep, the ol' big block Hemi's would outrun a SBC. So would the Chrysler wedge heads with more cubes. The big block Chevys (BBC) would do the same, as well as the big Fords. But there never was an engine line with so many different options, bores, strokes and so on with interchangeable parts ever produced. Ever. So for a guy on a budget who just wanted to go faster, the SBC was (and still is) a perfect playground.

Plus, GM is still committed to the ancient platform and is derided for it quite often, mostly because it's still a pushrod motor instead of using overhead cams like everyone else. So what, I say. The Corvette is produced and sold far cheaper than about all of it's performance contemporaries with equal or nearly equal performance. Certainly they have cornered the bang for the buck department - the money it takes a Ferrari or Porsche to outrun a Vette is considerable. Might be higher tech, but it costs cubic dollars more.

I've had the pleasure of owning four SBC equipped vehicles, and I've enjoyed each and every one of them. Biased? Hell yes I am.

And just because nothing sounds like one tuned up and "on the cam," here ya go:


Oh, Baaaayyyy Beeeee!


jed said...

Geezy peezy. Not 1 comment on the venerable SBC? What sort of motorheads read this ragsheet anyways?

I don't think I owned one. Maybe in my Monte Carlo. I remember Dad's '64 Impala with the 283 and a Powerglide. Later, we had a '69 Impala with a 350 and a Turbo Hydra-Matic.

But man, what a lifetime for that design. And of course, the endless debates about it vs. the Ford.

Jeffro said...

Geezy peezy. Not 1 comment on the venerable SBC? What sort of motorheads read this ragsheet anyways?

Heh. I was disappointed!!!

One of my mainstay points in the Ford vs Chevy debate is this: How many engine families did Ford have to build to keep up with just the one GM solution? I mean, really - the original Y? Or the Windsor? Or maybe the Cleveland? And just because they were in the same family didn't mean there was parts commonality.

OTOH, the new GM small blocks don't have a lot of parts commonality with the original 265 version. But there is even more they didn't change.

Not that I wouldn't take a warmed over 351C with a 'Stang built around it. Or an old Charger with a 383 wedge head. Love 'em all.

CGHill said...

I figured the main reason the small-block is still being used in the Corvette is because it sits low in the bay without a bunch of camshafts sitting on top - which makes for a lower center of gravity, always a good thing in a performance vehicle.

(And of course, it's spread to Camaro and the occasional Caddy because, well, the more, the merrier.)

The only small-block I've gotten to drive on anything resembling a regular basis was the 305 in the '76 Chevy Nova we bought back when I was part of a "we." Emissions controls and modest tuning notwithstanding, it was a sweet little (to the extent that five liters is "little") mill.