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With its big valves, performance cam, aluminum intake and Holley carburetor, Chevy's 350-horse L-79 327 became the blueprint for countless small-block performance engines built by enthusiasts. |
  Back in the early ‘50s, an immigrant engineer named Zora Arkus-Duntov penned a memo to Chevrolet management outlining his strategy for invigorating the division’s image. From that famous memo sprang one of the longest-lasting and most fruitful relationships ever enjoyed between car manufacturer and enthusiast. Chevrolet’s status as the most popular brand among the performance faithful is no accident. It’s the result of many years and dollars spent on hardcore high-performance research, development, and production.
The Chevrolet performance engine story has to start in 1955 with the release of the now universally famous small block. Debuting at 265 cubic inches, it didn’t take long for the tuning to begin. The Power Pack option became available in 1956, and in ‘57 the first of the famous 283 Fuel Injected models arrived. The next major small-block development was the 1962 327 cubic-inch 360-horse fuelie engine offered in the Corvette. With its 11.25:1 compression ratio, big-valve heads (1.94” intake, 1.50” exhaust) and solid-lifter camshaft, the 360-horse fuelie engine was really the first of the small-block firebreathers.
1964 brought even more refinement (and horsepower) to the Fuel Injected 327. Larger valves (2.02” intake, 1.60” exhaust) and a much healthier camshaft (.485” int/exh lift, 346° int/exh duration) resulted in a whopping 375 horsepower! Produced in 1964-65, this engine was available only in the Corvette.
By 1966, the new Mark IV big block (discussed later) assumed the role of top performance powerplant at Chevrolet. This didn’t mean, however, that performance small blocks would fall by the wayside. A new 350-horse 327, known by Chevy fans as L-79 (its RPO code), was released for duty in Corvettes, Chevelles and Chevy IIs. Although not quite as powerful (at least on paper) as the 375-horse fuelie engine of previous years, the wider applications meant many more were on the streets, which makes the L-79 the most popular of the ‘60s small blocks. With an 11:1 compression ratio, 2.02”/1.60” valves, a hydraulic camshaft measuring .447” int/exh lift, 342° int/exh duration, and a high-rise aluminum intake topped by a Holley 4-bbl, this engine exemplifies the type of performance small block a countless number of enthusiasts have built over the years.
Chevrolet’s involvement in the pony car wars began in 1967 with the Camaro, and this new platform would spur the development of perhaps the most talked-about small block to come from Chevrolet: The 302 Z/28 engine. Since we’ve been running a series of articles on the 302 by noted Chevrolet author Wayne Guinn in the past few issues of Restoration Review, including another on engine preparation in this issue, we won’t go into detail about the powerplant here. Suffice to say, however, that the 302 small block is legendary in its performance and reliability.
The last great small-block Chevy of the muscle car era arrived in 1970. The LT-1 350 was developed for the 1970 Corvette, and included most of the good stuff from the earlier hot-rod small blocks along with a few new pieces. The engine used 4-bolt main bearing caps, a forged-steel crank and special connecting rods (the famous LT-1 “pink” rods) that were shot-peened and magnafluxed by the factory. Forged pistons and big-valve (2.02”, 1.60”) heads combined to create the engine’s 11:1 compression ratio. The mechanical camshaft had .458” intake and .484” exhaust lift, and duration figures of 317° intake and 346° exhaust. A high-rise aluminum intake manifold was again topped with a Holley 4-bbl carburetor. Rated at 370 horsepower, the LT-1 was the most powerful production carbureted small block released by Chevrolet.
Of course, Chevrolet built more than small blocks to power their cars through the years. The basic rule of engine design from the late ‘50s to the early ‘70s was simple: Bigger is better. Displacements almost doubled during this time period, which usually meant a manufacturer had both small- and big-block engines. Chevrolet actually had two big block designs: The 348/409 “W-engines” and the Mark IV series.
The W-engines, so called due to the shape of their valve covers, were adapted from a truck design and made their passenger car debut displacing 348 cubic inches in 1948. The early 348s were decent performers, but things really started to pick up once the 348 was enlarged to 409 cubic inches in 1961.
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