The Z28 is worshipped by legions of fans and is even begrudgingly respected by some whose loyalties lie with its competitors. It was conceived by Chevrolet’s Product Promotion Engineering Manager Vince Piggins, to pummel the Ford Mustang in the Sports Car Club of America’s (SCCA) Trans-Am Championship series. Race-prepped versions of the 1967 Z/28 helped instigate the on-track pony car wars, and Roger Penske’s team – with driver Mark Donohue – went on to dominate the 1968 and 1969 seasons.
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The first-generation (1967-1969) Z/28s were icons of their era, in both street and race trim.For 1970-1974, Z28s were built on the second-generation of the F-body platform. Following the 1975-1976 hiatus of the nameplate, the 1977 edition arrived and was indicative of a decade of change in the auto industry, federal emissions and safety requirements, social norms, and more.
Accordingly, we thought it would be interesting to compare the 1967 Z/28 to the 1977 Z28, highlight a selection of developments, and touch upon a few of the circumstances that led to them.The 1967 Z/28 was limited to a maximum engine displacement of 5.0 liters (305 cubic inches) by SCCA rules, so Chevrolet engineered a V-8 that employed a 4.00-inch-bore 327 block and a 3.00-inch-stroke 283 crankshaft to arrive at 302 cubic inches.
It was fitted with forged bottom-end components, an aggressive solid-lifter camshaft, free-breathing heads with 2.02/1.60-inch valves, a high-rise aluminum intake manifold, Holley carburetor, dual exhaust with a deep-tone muffler, and an 11:1 compression ratio.
The hot small-block was significantly underrated at 290 hp and 290 lb-ft of torque in street trim and reported to make power all the way up to 7,000 rpm.The Camaro’s RPO Z28 Special Performance Package also came with heavy-duty cooling and a 3.73:1-ratio 12-bolt rear end with a radius rod on the passenger side to reduce wheel hop. Positraction was recommended and additional gear ratios were available, but a Muncie close-ratio four-speed and power front disc brakes were required at extra cost.