The Z/28 was released on December 29, 1966, just in time to run in the 1967 Trans-Am series. Its public introduction was low key, and many Camaro buyers who didn’t see the magazine coverage of the Z/28 weren’t aware it was available. The Z/28 was lost in the overall onslaught of Camaro promotion as GM bombarded the market to overtake the Mustang. The Z/28 option, costing $358.10, was available only in coupes and just 602
were sold.
Refinements were made to the 302 engine for 1968. Some of these upgrades came at the beginning of the model year, while others were rolled into production during mid-year. The 302 block was still shared with the 327 and the 350 engines, however it now boasted larger journals and a large journal crankshaft (2.10-inch rod journals and 2.449-inch main journals). First-production rods featured pressed pins and larger rod bolts, while second-production rods were changed to floating wrist pins. Pistons were also changed in mid-year. First-production 1968 302 pistons were similar to 1967 units, however the domes were notched across the entire head of the piston. Cylinder heads and camshaft usage
remained unchanged.
What the high-winding 302 lacked in low-end torque was made up in thrilling mid- and top-end acceleration. “Above 30 mph,” Car Life noted in a 1968 road test, “on winding mountain roadways, back country lanes and the rest of the types of roads that make driving worth doing, the Z/28 Camaro is an exhilarating vehicle. The Z/28 engine is a jewel, an outstanding performer by any yardstick.” The word was spreading about the hot Z/28 package, and sales rose to 7,199 units. The package price also rose to $400.25.
The biggest news for 1968 was the $500 cross-ram package homologated for Trans-Am competition and offered over-the-counter for the Z/28. The cross ram had first been conceived in 1966 for use with the big-block with conversion to small-block application taking place in the summer of 1967. Actually intended more for race use, customers could purchase and install the cross ram for street use themselves or have the dealer install it for them. Good for at least an additional 25 hp, the cross ram started with a special, dual-quad aluminum intake manifold with tuned runners and featured a pair of Holley 600-cfm double pumpers. The cross ram lacked manifold heat crossovers or chokes for the carburetors and was difficult to drive on the street. Its true purpose was on the racetrack, where it could add more horsepower to the high-winding 302.
The cross ram used a cowl-induction air cleaner and plenum to take advantage of the cooler, high-pressure air located at the base of the windshield. This cool air provided a denser charge and more power. While it was great on the racetrack, most testers found it impractical for street use.
“If the Z/28 isn’t a bona fide racing car—in street clothing—then we’ve never seen one,” observed Road & Track. The cross ram was available over Chevy dealers’ parts counters in December 1967, in time for Chevrolet to homolagate it for 1968 SCCA competition. By the end of the 1967 season, the Penske/Donahue team had sorted out the gremlins in their Z/28 and, thanks to improvements like the cross ram, won the 1968 Trans-Am championship.
The Z/28 truly came into its own in 1969. “News of Roger and Mark’s Trans-Am expedition has finally reached the Chevrolet marketing minions,” noted Sports Car Graphic, “and they’ve caught the fever.” After two years of racing and dozens of magazine road tests, Chevrolet marketing was finally getting behind the Z/28 and carrying the word from Detroit to dealers nationwide.
The Z/28 went through a transition to becoming a balanced street performance car rather than an uncivilized brute wearing painted suspenders.
When it came to the 302 engine, the Z/28 was not without its detractors. The complaints didn’t stem from the engine’s innate ability to wind to high rpm. Instead, questions arose about the 302’s merits as a street performance engine. Corvette Chief Engineer Zora Arkus Duntov called the 302 “an artificial engine built to meet an artificial class limit.