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GM rocked to a new '70s beat

The muscle car's attributes changed throughout an eventful decade

It was a time when disco was sweeping the land and General Motors was rocking to a new beat with the introduction of its second-generation "pony" car.

During the early part of the 1970s, performance cars would be hot, although perhaps not as fast or quick as they were at the peak of the muscle car era in 1970. By the mid1970s, speed and horsepower would be fond memories.

The second-generation Camaro made its debut early in 1970 (production problems delayed introduction from fall of 1969) with much acclaim from the automotive press. It had a buff new body and an all-new high-performance 1970 1/2 (remember, it was late) Z/28 package.

The first-generation Z/28, introduced in the fall of 1966 and running until 1969, had carved its own niche with the famous 302-cubic-inch V8, which made them legal (and necessary) for the Sports Car Club of America (SCCA) Trans Am racing series.

By 1970, a change in the SCCA rules allowed destroking larger engines to meet the 305-cubic-inch maximum. Not only did it mean Chrysler could shorten the crankshaft stroke of its new 340-powered Challengers and 'Cudas to meet competition guidelines, but Chevrolet no longer needed the high-revving, soft-on-torque 302 on the street.

Instead, it took advantage of he rules and switched to a new, treet-friendlier 350-cube motor which was destroked to 305 ubes for racing) that made 360 horsepower and the Z/28 a lot more fun to drive. The engine - the infamous LT1 - was pretty much the same as the one powering the Corvette that year, although the 'Vette made 10 more horses.

It came with a four-barrel carburetor, 11: 1 compression ratio, plus all the performance goodies found in the Chevy parts bin - solid-lifter camshaft, heavy-duty radiator, dual exhaust, and, since the Z concept was always as much about handling as it was horsepower, a special performance suspension consisting of larger sway bars and beefier springs.

The LT1 in the '70 1/2 Z/28 made most of the engines in the Chevy lineup green with envy, right down to the 250-cubic-inch inline six-cylinder that found its way into a surprising number of models of the svelte-looking Camaro coupe. The only thing with more moxy (at least in terms of peak numbers) was the 375-horsepower 396-cubic-inch V8, available for '70 only, but not in the Z/28. with an automatic.

Compared to the 1969 models, the new car was given a complete face-lift with a square, egg-carton-style grille and a wider, longer footprint. The basic chassis would remain the same through the 1981 model year.

Young drivers fell in love with the car, with its fresh, new look and great handling characteristics. But, storm clouds quickly appeared on the horizon in the form of gasoline shortages and tougher pollution regulations.

The very next year saw a reduction in the compression ratios of all GM's performance engines. The Z/28's power dipped to 330. By 1972, GM changed its rating system from "gross" to "net" (power with all the accessories hooked up and running) and horsepower sagged to 255, although it was essentially the same engine. The post-muscle-car-era gap slowdown was beginning to show.

The Z/28 would return in 1977 as a full model rather than an option package. But then, the car had become a paper tiger. It still had the 350 engine, but power barely scratched the 200 mark.

Not until 1993 did the Z/28, with the rebirth of the LT-1 designation, although with a hyphen this time, regain some of its fire-breathing glory. By then, disco was gone, punk rock was in, and the whole generation of Boomers had moved on to drive sport utility vehicles.

But, from 1970-'73, the Camaro, especially the Z/28, boltstered GM's image, both on the track and on the street. And, for the lucky people who owned one of these great machines, a piece of automotive history - and story telling - will be handed down from generation to generation.

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