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Following the introduction of the Camaro in 1967, Chevrolet, together with Roger Penske, owner of a Chevrolet dealership, wanted to enter the new Camaro in the Trans Am Racing Series... In mid-year, the Z28 would be announced.
To compete in the series, the engine displacement, under the Sports Car Club of America rules, could not exceed 305.1 cubic inches (5-litres), so Chevrolet engineers took the crankshaft from the 283 with its 3-inch stroke and put it into a 327 block with its 4-inch bore, resulting in a 302 displacement. Hence, the Z28 was born.
While Chevrolet officially rated the 302 V-8 engine at 290 horsepower, early dyno-tests showed it to be actually close to 350 bhp. It was fitted with solid lifter camshaft, Fuelie heads, an aluminium intake manifold and 800 cfm 4-barrel Holley carburettor - a combination which took the pony car world by storm.
On the track in the Trans Am Racing Series, the owner-driver team of Roger Penske and Mark Donohue won a staggering ten out of thirteen races for Chevrolet in 1968, and followed this up with a further eight out of the twelve race series in 1969. The Z28 was proving to be almost untouchable.
Success on the track was reflected in the popularity of Chevrolet's new creation, and sales figures showed that they were onto a winner. Apart from a face-lift in '69, and some mechanical modifications, the first generation Z28 remained unchanged until the "All New" 1970 model made its debut in February that year.
The body now took on a new sleeker appearance with a semi-fastback roof-line and "shark-nose" front end styling. But there was more news in 1970 than simply a new body and some chassis changes. The engine was the new LT-1 version of the 350 cu. in. V-8 small-block which came with 4-bolt mains, solid lifters, forged aluminium pistons, 800 cfm Holley carburettor, and was rated at 360 horsepower.
The 1971 model Z28 was virtually unchanged, although the horsepower was now pegged at 330. 1972 saw the horsepoewr dive to 255, due to the safety and pollution devices which were being Federally-mandated each year. In 1973, the LT-1 high performance solid lifter engine was dropped in favour of the L-82 350 cu. in. fitted with hydraulic lifters and rated at 245 bhp. Also in this year the chrome bumpers were replaced by the Federally-mandated 5mph bumper that was standard equipment on all Camaros.
The 1974 Z28 was almost identical to the previous year, but due to the pressures of the Arab oil embargo and emission control freaks, there was no Z28 in 1975 or 1976, but was re-introduced half way through the 1977 model year. In fact, the Camaro and the Firebird almost bit the dust, but for an eleventh hour executive decision which secured their continued production.
Once again, styling for the 1977 1/2 Z28 was very similar to the '74. the engine was now an LM-1 350 cu. in., however the power output by now had fallen to just 170 bhp. This was improved to 185 horsepower for the following model year, a year which also heralded the new "bumperless" look. The purpose of the new rubberised front end, was to provide better impact protection. To complement this new style, the rear bumper was also colour coded to match the body. Another feature on the 1978 model was a bolt-on fibreglass hood scoop; however, this would not become functional until the 1980 model. |
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