The Z/28


When Chevrolet introduced the Camaro in the summer of 1966 they knew that they had a contender for the SCCA Trans-Am Racing Series sedan class, created just that year. Although GM had officially banned racing involvement in 1963 there were plenty of people at Chevrolet itching to get back into the game, including Chevrolet engineer Vince Piggins, who may have played a key role in the creation of that class.
8hspace.gif (810 bytes)"I felt in my activity," Piggens said, "which deals with product promotion and how to get the most promotional mileage from a car from the performance standpoint, that we needed to develop a performance image for the Camaro that would be superior to the Mustang's. After Ford released the Mustang they had about two years on us before Chevrolet could get the Camaro into the 1967 product line."


Penske/Donohue Sunoco Camaro, 1969

 8hspace.gif (810 bytes)"Along comes SCCA in creating the Trans-Am sedan racing class for professional drivers in 1966, aimed for the 1967 season. I made it a point to have several discussions with SCCA officials-notably Jim Kaser, John Bishop, and Tracy Byrd - and one thing led to another. I suggested a vehicle that would fit this class and, I believe - supported by what Chevrolet might do with the Camaro - it gave them the heart to push ahead and make up the rules, regulations, and so forth for the Trans-Am series. I feel this was really the creation of the Trans-Am series as we know it."
8hspace.gif (810 bytes)The only problem was that while they had the car, they didn't have an engine. The Trans Am Series had a displacement limit of 305 cubic inches, and Chevy didn't have anything close to that. They toyed with the idea of using the 283, but instead they created a new engine by mating the 4 inch bore block of the 327 (and the 350) with the 3 inch stroke crank of the 283, coming in just under the limit at 302.4 cubic inches. More details on the 302 are available here.
8hspace.gif (810 bytes)They also didn't have a name. In a replay of the struggle to come up with the name "Camaro" they tried several different approaches, including Piggens' choice, "Cheetah." The one that came closest to actual use was "302 Special Performance." In the meantime the bureaucratic workings at Chevrolet had already assigned a Regular Production Option code to what they were calling the Special Performance Package. Apparently, RPO Z27 had been assigned to the SS although it didn't appear under that option until 1969, and the new option was assigned the next number, Z28. It is not known when the decision was made to use the RPO code for the name, but probably not until after the first cars were built.

1967 Z/28 RS
8hspace.gif (810 bytes)Sometime in the middle of January the first cars equipped with RPO Z28 appeared, and they carried no external badges denoting the option. Most of them went to dealerships with an active racing involvement, such as the Yenko and Penske dealerships in Pennsylvania, Nickey Chevrolet in Chicago, and Tonkin in Oregon. Chevrolet only sold 602 Z/28s that first year, 398 less than required to homologate the car under the FIA Group 1 rules. Chevrolet, always a master at bending the rules, got around the problem by homologating the 350 car under Group 1 rules, then qualifying the car with the Z/28 option under Group 2 rules.

1969 Z/28
8hspace.gif (810 bytes)The plan worked, with the Camaro taking the title in '68 and '69. The Z/28 got its own identification badges in '68 and the sales took off, with 7,098 of the total 235,147 Camaros sold that year carrying the Z/28 option. They did even better in '69 when 20,302 Z/28s out of 243,085 were sold.
8hspace.gif (810 bytes)As originally conceived, the Special Performance Equipment Option consisted of the F41 heavy-duty suspension, front disc brakes, metallic-lined rear drum brakes, 24:1 quick-ratio steering gear, 15x6 Rally wheels with 7.75x15 tires, a special air intake, the M21 close-ratio 4-speed transmission, and the 302 V8 engine. When the option hit the order sheets, however, it didn't include the brakes or the transmission. You were required to add these options seperately, adding another three to four hundred dollars to the standard four hundred dollar price of the Z/28 option.

1968 Z/28
8hspace.gif (810 bytes)For '68, the engine stayed basically the same, but received the new large journal crankshaft. A quicker steering ratio became standard, 21.4:1, with an even quicker ratio as an option, 17.9:1. The D80 spoiler option became available, as did a thicker front sway bar. The Z/28 got the new five leaf rear springs along with the rest of the Camaros, and a better suspension.

302 Crossram
8hspace.gif (810 bytes)There were also two important "Service Options" available, which meant you had to buy them from the dealer's parts counter and install them yourself. These were the four wheel disc brake package, and the dual four barrel intake. This intake was never offered as a Regular Production Option, and is not considered original equipment on any car.

Chevrolet Advertisement
8hspace.gif (810 bytes)The 1969 Z/28 was different from the '68, with quite a few pieces of optional and standard equipment coming and going during the extended production run. The ZL2 Special Ducted Hood became available in mid-December. Contrary to popular belief, Chevrolet never called it "Cowl Induction." That name appeared on a similar system for the 1970 Chevelle. Chevy advertised it as the "Super Scoop", and later began referring to it as "air induction" in internal memos relating to the Pace Car replicas. The previous Z/28 system ducted the air from the cowl area through the firewall.

8hspace.gif (810 bytes)This hood was also available in fiberglass to work with the crossram intake manifold, which was again a service option in '69. This hood had an oval mating area on the underside to fit the oval air cleaner of the crossram. This package was offered over the counter in order to homologate it for racing.
8hspace.gif (810 bytes)Other changes for '69 include a four-bolt main bearing block and Firestone E70-15 Sports Car 200 tires in place of the standard Goodyears. The four wheel disc brake package became a standard option under RPO JL8, although only 206 were ordered this way. There were many more ordered as a service option, and the two systems were not the same. You can find out the differences in the Rare Car section. In addition, the RPO NC8 Chambered Exhaust option came and went, because it was both popular (with the customers) and unpopular (with the police) at the same time.
8hspace.gif (810 bytes)The Z/28 302 engine was rated by the factory at 290hp. Although everyone says that the engine was underrated, I have not seen any tests done to determine the actual horsepower. Estimates have ranged from 300 hp to 500 hp. The numbers that have been documented come from the actual Penske/Donohue race cars.
8hspace.gif (810 bytes)Pat Ryan of Unfair Advantage Racing owns one of the original 1967 cars. He still races it it the Sports Car Vintage Racing Association. The engine, as prepared by Traco engineering, puts out 398 hp at 6,800 rpm. In 1968 the Traco engines put out varying horsepower in different stages of tune, but I have seen the following numbers: 441.5 @ 7,400, 419.5 @ 6,800, and 458 @ 7,100. These figures were taken with the single four barrel setup.
8hspace.gif (810 bytes)So how powerful was the production 302? Probably around 350-400 horsepower would be a good guess. No bad from 302 cubic inches!

8hspace.gif (810 bytes)The Z/28 package had several significant changes through the extended production run. Here are the five different versions offered:

1969 RPO Z/28 CHANGES

(These changes were taken from dealer order book revisions from 1969)

Version A: Dated September 26, 1968
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" 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 trans., power disc brakes are ordered. Positraction rear axle recommended.
Price 458.15
Note: no tach required

Version B: Dated October 18, 1968
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" V8 engine with bright accents; chambered dual exhaust system; Z/28 emblems on grille, front fender and rear panel; special front and rear suspension; rear bumper guards; heavy-duty radiator and temperature-controlled fan; quick ratio steering; 15 x 7 wheels with trim rings; E70 x 15 special white lettered blackwall tires and special paint stripes on hood and rear deck. Avail. only when 4-speed transmission, power front or four-wheel disc brakes are ordered. Positraction rear axle recommended.
Price 458. 15
Note: chambered exhaust part of option. Notice JL-8 (four-wheel discs) recommended

Version C: Dated January 2, 1969
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" V8 engine with bright accents; dual exhausts; Z/28 emblems on grille, front fender and rear panel; special front and rear suspension; rear bumper guards; heavy-duty radiator and temperature-controlled fan; quick ratio steering; 15 x 7 wheels with trim rings; E70 x 15 special white lettered blackwall tires and special paint stripes on hood and deck. Avail. only when tachometer gauge or special instrumentation, 4-speed trans., power front or four-wheel disc brakes are ordered. Positraction rear axle recommended.
Price 473.95
Note: tach now required; no longer has chambered exhaust as a standard feature

Version D: Dated April 1,1969
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" V8 engine with bright accents; dual exhausts; Z/28 emblems on grille, front fender and rear panel; special front and rear suspension; rear bumper guards; heavy-duty radiator and temperature-controlled fan; quick ratio steering; 15 x 7 wheels with special center caps and trim rings; E70 x 15 special white lettered blackwall tires; auxiliary front valance panel and rear deck spoiler plus special paint stripes on hood and rear deck. Available only when tachometer gauge or special instrumentation, 4-speed transmission, power front or four-wheel disc brakes are ordered. Positraction rear axle recommended.
Price 506.60
Note: spoilers now required

Version E: Dated September 18, 1969
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" V8 engine with bright accents; dual exhausts with bright tips; Z/28 emblems on grille, front fender and rear panel; special front and rear suspension; rear bumper guards; heavy-duty radiator and temperature-controlled fan; quick ratio steering; 15 x 7 wheels with special center caps and trim rings; E70 x 15 special white lettered blackwall tires; auxiliary front valance panel and rear deck spoiler plus special paint stripes on hood and rear deck. Available only when tachometer gauge or special instrumentation, 4-speed transmission, power front disc brakes are ordered. Positraction rear axle recommended.
Price 522.40
Note: notice chrome tail pipes standard on or about May 19, 1969.

Version F: Dated November 3, 1969
8hspace.gif (810 bytes)Z/28 Special Performance Package: Model 12437 only. Includes 302" V8 engine with bright accents; dual exhausts with bright tips; Z/28 emblems on grille, front fender and rear panel; special front and rear suspension; rear bumper guards; heavy-duty radiator and temperature-controlled fan; quick ratio steering; 15 x 7 wheels with special center caps and trim rings; E70 x 15 special white lettered blackwall tires; auxiliary front valance panel and rear deck spoiler plus special paint stripes on hood and rear deck. Available only when tachometer gauge or special instrumentation, 4-speed transmission, power front disc brakes are ordered. Positraction rear axle recommended.
Price 522.40
Note: These are used for comparison. There are many documented cars which do not fall into these guidelines. Anything could have happened on the assembly line.

8hspace.gif (810 bytes)Other changes occurred in the '69 model year. Early '69 Z/28s used a Y55 top post battery, but Chevy went to a side post Y77 in February. A few months later this was replaced by the Y89, which used the same bolt size for the positive and negative terminals.
8hspace.gif (810 bytes)The Z/28 got single piston calipers on the disc brakes, as opposed to the four piston calipers in '67 and '68. You could also order the factory 4 wheel disc brake systerm, RPO JL8, but there were problems with parts availability during the year, and there were several stop orders issued, delaying delivery of the cars.
8hspace.gif (810 bytes)The console and guages were the same as used in 1968, but the woodgrain pattern was different. In 1969 rosewood replaced walnut on all the woodgrain accents.
8hspace.gif (810 bytes)The stripes were larger on the rear deck in '69 than on previous years. You could also order your Z/28 with the stripes deleted.

8hspace.gif (810 bytes)The Z/28 became a legend almost from the start. While the new Camaros are wonderful cars, there is nothing quite like a 1969 Z/28!