The Z/28 option code was introduced in December 1966 for the 1967 model year. It was the brainchild of Vince Piggins, who conceived offering "virtually race-ready" Camaros for sale [14] from any Chevrolet dealer.[15] This option package was not mentioned in any sales literature, so it was unknown to most buyers.[16] The Z/28 option featured a high-output small-block 302 cu in (4.9 L) V-8 that had been designed for racing in the 5 litre (305 cu in) class in the then very popular Trans-Am racing series. It was intended as a head-to-head competitor for the Ford Boss 302 Mustang. It had a 3 in (76.2 mm) stroke crankshaft with 4 in (101.6 mm) bore, an aluminum intake manifold, and a 4-barrel vacuum secondary 780 cfm Holley carburetor.
Advertised power of the 302 was listed at 290 hp (216 kW) - an under-rated figure.[16] Chevrolet wanted to keep the horsepower rating at less than 1 hp per cubic inch, for various reasons (e.g. insurance and racing classes). The factory rating of 290 hp occurred at 5300 rpm, while actual peak for the high-revving 302 was closer to 360 hp (268 kW) (with the single four barrel carb) and 400 hp (298 kW) (with optional dual-four barrel carbs) at 6800-7000 rpm.
The Z/28 also came with upgraded suspension, front disc power brakes, and a 4-speed Muncie close-ratio manual transmission. Posi-traction was available as an option. Cosmetically, the Z/28 came with wide racing stripes on the hood and trunk lid (that could be "optioned-out" a no charge), '302' front fender emblems on the '67 and early '68 cars, and 'Z/28' emblems in late '68 and '69. It was also possible to combine the Z/28 package with the RS package.
A total of 602 Z/28s equipped Camaros were sold in 1967, along with approximately 100 Indianapolis Pace Car replicas.[17] The 1967 and 1968 Z/28s did not have the cowl induction hood, optional on the 1969 Z/28s. The 1967 Z28 received air from an open-element air cleaner or from an optional cowl plenum duct attached to the side of the air cleaner that ran to the firewall and got air from the cowl vents. 15-inch rally wheels were included with Z/28s while all other 1967-9 Camaros had 14-inch wheels.
The origin of the Z/28 nameplate came from the RPO codes - RPO Z28 was the code for the Special Performance Package. RPO Z27 was for the Super Sport package.
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