The 302 was the product of Chevrolet’s desire to compete against Ford in the SCCA Trans Am road racing series in the division limited to 305 cubic inches. Credited to Chevrolet engineer Vince W. Piggins, the 302 was a combination of the 327 engine block and the 283 crankshaft resulting in a displacement of 302.4 cubic inches. The Camaro Z28 was offered to consumers as a street legal race ready performance car.

The Z28 RPO was a Camaro only RPO first made available for the 1967 model year. It was officially known as a “Special Performance Package”. The now famous 302 engine could not be had without ordering one or more of the following Z28 RPO packages.

1967
Special Performance Package – Option Number Z28, Ordering Col-Code 48-3, List Price $340.00
“Model 12437 only. Includes 302-cu.-in. V8 engine, closed positive ventilation, dual exhaust with deep-tone mufflers, special front and rear suspension, heavy-duty radiator and temperature-controlled fan, quick ratio steering, 15 x 6.00 wheels, 7.35 x 15 NF nylon red strip tires, 3.73 ratio axle and special paint stripes on hood and rear deck. Available only when 4-speed close-ratio transmission, power brakes, front disc brakes or heavy-duty front disc brakes with metallic rear brakes are ordered. Positraction rear axle recommended.”
(Model 12437 was the Camaro sport coupe. The Z28 option was not available on model 12467, the Camaro convertible)
Special Performance Package Plus Plenum Air Intake – Option Number Z28, Ordering Col-Code 48-4, List Price $415.00
“Includes special air cleaner and duct system, furnished loose.”
Special Performance Package Plus Exhaust Headers – Option Number Z28, Ordering Col-Code 48-5, List Price $740.00
“Includes special tuned exhaust headers, furnished loose.”
Special Performance Package Plus Plenum Air Intake and Exhaust Headers – Option Number Z28, Ordering Col-Code 48-6, List Price $815.00

1968
Special Performance Package – Option Number Z28, List Price $380.00
“Model 12437 only. Includes 302-cu-in V8 engine, dual exhaust with deep-tone mufflers, special front and rear suspension, rear bumper guards, heavy-duty radiator and temperature-controlled fan, quick ratio steering, 15” x 6.00” wheels, E70 x 15 special nylon tires, 3.73 ratio axle and special paint stripes on hood and rear deck. Available only when 4-speed transmission, power brakes and front disc brakes are ordered. Positraction rear axle recommended.”

1969
Special Performance Package (Z28) – RPO Number Z28
“Model 12437 only. Includes 302-cu-in V8 engine, dual exhaust with deep-tone mufflers, special front and rear suspension, rear bumper guards, heavy-duty radiator and temperature-controlled fan, quick-ratio steering, 15 x 7 rally wheels, E70 x 15 special white lettered tires, 3.73 ratio axle and special rally stripes on hood and rear deck. Available only when 4-speed transmission, power disc brakes are ordered. Positraction rear axle recommended.”

As with all other small block Chevrolet V8 engines, the 302 block was stamped with a suffix code. Several 302 suffix codes were used over the 1967-1969 model years. In 1967, suffix codes MO and MP were used. In 1968, suffix code MO was used. Suffix code DZ was used in 1969. Some sources state that some DZ blocks were seen in late 1968.