Chevrolet Small-blocks Number 5


The 4.0-inch bore family 1962-1998

The 302 continued

For the 1968/69 racing seasons, Mark Donohue was a winner driving a 302-powered Chevy in the Trans-Am championships. The stroke/bore and the rod/stroke geometries make the 302 a natural for high RPM and racing as well as a very dependable street driving power plant. All components used in the Trans-Am had manufacturer production part numbers and had to be available to purchase at authorized dealerships. However, the 302, at its height, from 1968 until 1976 ran in SCCA Formula 5000 Championship series in the open-wheel class for a lower cost.

These engines, built up by Traco Engineering, Al Bartz, and Falconer and Dunn, saw use around the world, but  particularly in New Zealand and Australia where the 302 outperformed the Repco-Holden V8 power plant. The head and block weighs around 1350 pounds while producing 525 to 550 horsepower with the five-speed, magnesium trans-axle, 10×13-inch tires in front with 20×15-inch on the rear. Mounted on magnesium wheels, the 302 was a formidable opponent on the Aussie tracks.

The Holden with this engine would do 0-60 in 2.8 seconds and attain a top speed of 180 mph in the process. Racer Bruce Allison said that “during the races in the ’70s, they would never start in first gear; the car had too much torque.They would always start in second and, producing high torque up to third and fourth gear, it was difficult not to make the tires spin.” These cars were for racing with a Lucas-McKay mechanically timed fuel injection system on the intake, bolted to ported double-hump cast-iron heads, a rev-kit to fit the roller lift cam, roller bearing rocker arms, and a stock-production crankshaft. The 302 engine had lasting impact on the U.S. racing circuits with its high count of front-finishing cars as well as a high degree of success on the international Grand Prix circuits, driven by legendary drivers like Jody Scheckter, Mario Andretti, David Hobbs, and Brian Redman.

The 327

The 327-cubic-inch (5.35L) V8 engine made its first appearance in 1962. The engine with its 4.0-inch bore and a 3.25-inch stroke has a range of from 210hp (157 kW) up to 375hp (280 kW), depending on depending on which carburetor and/or fuel injection, as well as the choice of cylinder heads, pistons, and intake manifold. For 1962, with a solid lifter cam made by Duntov, the 327, with one Carter four-barrel carburetor, can develop 340hp (254kW) producing 344 lbs.-ft. (466 N-m) of torque, but if you picked the Rochester mechanical fuel-injected version, the hp bumped up to 360 ((268 kW), and the injection upped the torque to 352 lbs.-ft. (477 N-m).

The 327 L-76 version, offering 365 hp (272 kW) in the carbureted model became available in the 1964 model year while the L-84 fuel-injected engine could give up to 375hp (280 kW). The naturally aspirated L-84 V8 is the most powerful small-block in the GM arsenal until the third generation LS6 in 2001 surpassed it by developing 385hp (287 kW). A big change in the 1968/69 model year for the 327 occurred when the main journal increased from 2.30 inches (58.4 mm) to 2.45 (62.2 mm).

The 327-cubic-inch L-79 engine is the stuff legends are made of but is nothing more than an L-76 with the 2.02 Corvette heads with the solid lifter Duntov cam replaced with the #151 hydraulic cam and 11.0:1 forged pistons, and forged push rods; it also sports a forged crankshaft. This 327 350hp power plant can perform in the same arena as a lot of the big-blocks with pleasing results. Checker offers the 327 optionally for ’66, and the Studebaker Avanti II was also powered by the 327 and its siblings. In 1968, Holden Australia also imported the 327.

The post Chevrolet Small-blocks Number 5 appeared first on Muscle Car Fan.