The 1967-69 Camaro Z/28 and its 302 powerplant were the product of Chevrolet’s desire to compete against Ford in the SCCA Trans Am road racing series. The Camaros and Mustangs raced in the 2.0L+ class that was limited to 5.0L / 305 cubic inches. Credited to Chevrolet engineer Vince Piggins, the 302 was a combination of the 327 block (4″ bore) and the 283 crankshaft (3″ stroke), resulting in a displacement of 301.59 cubic inches (4.9L). The oversquare bore to stroke ratio, combined with large valve heads and solid lifter camshaft, gave the 302 it’s high revving demeanor. Rated at a conservative 290 horsepower, the Camaro Z/28 was marketed to the public as an “exceptional touring machine”. More specs here…

The Z28 RPO (Regular Production Option) was a Camaro only upgrade option, known officially as a “Special Performance Package”. GM organizes RPO codes into component groups, the engine component group containing RPO codes K01-L99. The “special items” component group contains RPO codes Z01-Z99, including the Z28 option code. The now iconic 302 engine was available only by ordering one of the following Z28 performance 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.”

 

If Z28 is the RPO code, what does the “DZ” code specify? As with other small block Chevrolet V8 engines, the 302 block was stamped with an engine ID code, part of which is the “suffix code”. The suffix code specifies the engine’s displacement in cubic inches (CID), horsepower rating (HP), installed equipment, and vehicle application. Three suffix codes were used for the 1967-69 302 engines: MP, MO, and DZ. MP was used for 1967, MO was used for both 1967 and 1968, and DZ was used for 1969 only. 1967 and 1968 MP and MO blocks had 2-bolt mains. Only 1969 DZ blocks (casting numbers 3932386, 3956618 and 3970010) had 4-bolt mains.

The DZ suffix code specifies a 1969 302 CID, 290 HP engine with 4-barrel carburetor and manual transmission for a Camaro Z/28.

The photo below shows a rare 1969 Camaro Z/28 with dual Holley 4-barrel carburetors on the aluminum “Crossram” intake manifold. Note the “DZ” on the driver side cylinder head (written on the assembly line). Also note the accessory holes drilled in the head. Accessory holes were added to all 1969 and up cylinder heads.