The Origins Of The Chevrolet Camaro Z/28

The Sports Car Club of America caught the pony car zeitgeist with the Trans-American Sedan Championship, better known simply as Trans-Am. Evolved from the SCCA’s A- and B-sedan club-racing categories, the series had two classes that ran on track together; the more relevant of these was the Over 2-liter class. Wheelbase was limited to 116 inches, engine displacement to five liters (or 305.1 cubic inches), and regulations required that eligible production vehicles have a rear seat. Trans-Am was also open to FIA Group 2 Touring Cars, which required a minimum of 1,000 cars built for public consumption.

For the series’ 1966 debut, Chevy largely sat out as it stuck to its no-racing agreement with Ford and Chrysler – then watched as the other guys competed in Trans-Am. Enthusiast magazines covered the series with fervor – hell, Jerry Titus, one of Shelby’s drivers, was an editor at Sports Car Graphic magazine – and where there’s ink there’s promotional value. Chevy wanted in. Once he got GM’s blessing to do a version of the upcoming Camaro pony car aimed at Trans-Am competition, Vince Piggins (then an assistant Chevrolet staff engineer) assured SCCA brass that Chevy would enter a car for the ’67 series. The car, the Chevrolet Camaro Z/28, would become the first SCCA Trans-Am-homologated pony car, thus ensuring its place in the history books—even if it never won.

1967: RPO Z28

1967 Chevrolet Camaro RPO Z28 – Forward 3/4

Once waves from Camaro’s initial splash started to ebb, Chevrolet quietly announced RPO Z28 – a package that never made it into the ’67 Camaro catalog. Z28 was (at least initially) not a model name – it was just an ordering code for the Special Performance Package (See sidebar). Z28 consisted of the following: a 302-cubic-inch V-8; dual exhaust; heavy-duty radiator with five-blade temperature-controlled fan; F41 suspension with stiffer springs (tapered monoleaf rears) and shocks; a right-side-only traction bar; quick-ratio steering; 15 x 6-inch Chevy Rally wheels with 7.35-15 nylon red-stripe tires; and an open 3.73:1 axle in a 12-bolt housing. Twin stripes on the hood and rear deck (relieved around the chromed Camaro callouts on either end) were also standard. There was no Z28 badging in ’67, although the name was prominently discussed in period media, and even appeared on the side of Roger Penske’s race car. Mandatory options included the $184.35 close-ratio Muncie M21 four-speed transmission and power-assisted front disc brakes ($121.15). If the optional tachometer was selected, it was marked all the way up to 8,000 rpm.

1967 Chevrolet Camaro RPO Z28 – Engine Bay

Chevrolet found its 302 cubic inches by mating a small-journal 327 block with a forged, Tufftrided 283 crankshaft – a recipe that Chevy had used in USAC sprint cars for some time. (The oversquare 4-inch bore and short 3-inch stroke meant the engine could rev harder for longer—perfect for racing.) The 800-cfm Holley four-barrel sat atop a high-rise dual-plane aluminum intake and beneath an open-element air cleaner. A set of 327 heads were used with 2.02/1.60 valves and 64-cc combustion chambers; with domed pistons the 302 made a stout 11:1 compression. The solid-lifter “Duntov 30/30” camshaft from the fuel-injected Corvette was pressed into service. Deep-groove V-belt pulleys offered high-revving security. The result was an advertised 290 horses at 5,300 rpm, though this rating was known to be conservative, designed to keep street cars insurable and maybe to keep from revealing too much to cross-town competitors in the Trans-Am series. Rev another 1,500 rpm higher, and you’d be closer to 350 horsepower.

Positraction was recommended but not included. A trunk spoiler and sintered-metallic brake pads and linings were also optional. Over-the-counter dealer-installed options included a cowl-attached cold-air system to collect dense air from the base of the windshield. headers, and a dual-four-barrel cross-ram intake manifold paired with two 585-cfm Holleys. Most other Camaro appearance options (Rally Sport package, vinyl top, and so on) were available, although you couldn’t get a convertible or SS with Z28. Automatic transmission and air conditioning were similarly unavailable. The enthusiast press was effusive. “Chevrolet’s version of the Shelby Mustang,” said Car and Driver. “With the Z-28 [sic], Chevy is on the way toward making the gutsy stormer the Camaro should have been in the first place.” Only 602 sold in ’67, but Chevy found a loophole to make everything legal.

1967 Chevrolet Camaro RPO Z28 – Headlight/header panel close

Much like the production cars, the Z28’s racing career got off to a slow start. While Ford relied on Carroll Shelby, Piggins turned to Roger Penske to field a team; Penske had a good relationship with Chevrolet, racing Lolas in Can-Am and Corvettes at Daytona and Sebring endurance events. Chevrolet didn’t want to be seen lending support at the track, so factory engineers and their equipment had to be there on the down-low, and Chevy management didn’t want to be responsible for Penske’s car testing on GM property.

Yet management was tired of losing – key members wanted victory and glory but didn’t want to put forth the effort needed to make it work. A quiet trip to GM’s Milford Proving Grounds helped; suspension, brakes, aerodynamics, and weight issues were all tackled over time, and Penske’s Camaros (led by engineer-driver Mark Donohue) soon won the Marlboro Speedway event in Maryland; Donohue also won the Las Vegas and Kent, Washington races. Chevrolet ended the season third in points…out of four manufacturers.

1967 Chevrolet Camaro RPO Z28 – Close head-on

1967 Chevrolet Camaro RPO Z28 – Interior

1967 Chevrolet Camaro RPO Z28 – Rear 3/4

1967 Chevrolet Camaro RPO Z28 – Taillight Detail

1967 Chevrolet Camaro RPO Z28 – Wheel detail

1967 Chevrolet Camaro RPO Z28 – Console Gauge Cluster

1967 Chevrolet Camaro RPO Z28 – Steering Wheel Horn Cap

1968: Camaro Z/28

1968 Chevrolet Camaro Z/28 – Front 3/4

Beyond the year-to-year changes that all Camaros received for 1968, the Z/28 (now with badging and a slash after the Z) received a handful of upgrades as well. Engines remained substantially the same, but larger connecting rod and main bearing journal diameters for ‘68 – from 2.00/2.30 inches, rods/mains, to 2.10/2.45 inches – were introduced; what’s more, Z/28s were upgraded to four-bolt main caps in the three middle positions (the outer caps remained two-bolt affairs). Tires changed to white-letter E70-15 rubber. Monoleaf rear suspension was swapped out in favor of four-leaf rear springs and staggered rear shocks. The fiberglass trunk spoiler remained optional. Production jumped nearly twelvefold, to 7,199 units. It remained Detroit’s only street-driven Trans-Am special.

For ’68, Chevy ran ads for the Z/28, which surely helped the sales effort. More positive press rolled in. “If the Z-28 [sic] isn’t a bona fide race car – in street clothing for this test – then we’ve never seen one,” said Road & Track. In a C/D driving comparison, where both the Camaro and Mustang were allowed to cheat equally while Sam Posey whipped both around Lime Rock Park, Posey preferred the Mustang while the Camaro found favor with the magazine staff.

But much of Z/28’s sales success has to be laid at the feet of the racing effort, which was sorted by the end of ’67. Has there been a bigger year-to-year turnaround than Chevy’s in the ’68 SCCA Trans-Am? Penske and Donohue went on an eight-race winning streak (Sebring, War Bonnet Raceway in Oklahoma, Lime Rock, Mid-Ohio, Bridgehampton, Meadowdale in Illinois, Circuit Mont-Tremblant in Quebec, and Loudon, New Hampshire) and won 10 of 13 races overall. Ford got spanked and Mopar wasn’t even a factor; Chevrolet won the championship with 90 points (the most allowed in the SCCA best-of-nine points system) to Ford’s 59.

1968 Chevrolet Camaro Z/28 – Side Profile

1968 Chevrolet Camaro Z/28 – Engine Bay

1968 Chevrolet Camaro Z/28 – Taillight Detail

1968 Chevrolet Camaro Z/28 – “Camaro” Door Card Emblem

1968 Chevrolet Camaro Z/28 – Speedometer

1968 Chevrolet Camaro Z/28 – Interior

1968 Chevrolet Camaro Z/28 – Headlight/fender detail

1969: Z/28’s Mass Appeal

1969 Chevrolet Camaro Z/28 – 7/8ths forward view

Camaro was treated to an aggressive new look for 1969, and the Z/28 package remained largely intact. The four-barrel Holley carburetor was now rated at 780 cfm rather than 800; wheels grew to 15×7. Initially available only with a flat hood, the ZL-2 Special Ducted Hood (better known today as the cowl-induction hood) became a mid-season option. The mandated power front disc brakes now used single-piston calipers, and the oft-criticized Muncie shifter was traded for a Hurst unit. The NC8 chambered exhaust system – essentially free-flowing chambered pipes – was initially standard, but the system shattered local noise ordinances nationwide, so Chevy reverted to a more conventional 2¼-inch muffler-equipped dual exhaust. A rare option: the Corvette-style JL8 four-wheel-disc brakes, available throughout the Camaro line. Z/28 production nearly tripled year-to-year, to 20,302 units. This, despite Ford’s own SCCA-homologated racing package, the Boss 302.

On track for ‘69, the Boss put up a better fight against the Z/28, but Chevy won the Trans-Am season 78 points to 64. Donohue took the bulk of Chevy’s victories – Loudon, Mont-Tremblant, Watkins Glen, Laguna Seca, Sears Point, Riverside – but ex-F1 driver Ronnie Bucknum won Mid-Ohio and Kent, Washington.

1969 Chevrolet Camaro Z/28 – Rear 7/8

1969 Chevrolet Camaro Z/28 – Side Profile

1969 Chevrolet Camaro Z/28 – Fender Badge Detail

1969 Chevrolet Camaro Z/28 – Underhood

1969 Chevrolet Camaro Z/28 – “302” hood callout

1969 Chevrolet Camaro Z/28 – Console gauge detail

1969 Chevrolet Camaro Z/28 – Interior

A Trifecta Collection

Owner Rich Fairser and 1967 Chevrolet Camaro

With only 602 ’67 Z/28s built nearly three-score years ago, with many raced and more wrecked, finding any genuine ’67 Z/28 is tough these days. (Just 235 appear on the 1967 Z/28 National Registry.) So, imagine the entire first-generation Camaro Z lineage under one roof – painted more or less the same color scheme (blue with white stripes) to boot – as we did here. Rich Fairservis of Chandler, Arizona owns the historic trio here: the ’67 in Marina Blue sporting 4.88 gears with Positraction, console, tilt wheel, and the cowl plenum air cleaner assembly; the ’68 in Grotto Blue wearing a Rosewood steering wheel, AM radio, spoilers, original smog system, and little else; and the ’69 in Le Mans Blue with Posi, power steering, console, AM radio and rear spoiler among the options.

Other homologation specials would come and go – Pontiac’s Trans Am in ’69, the Mark Donohue AMC Javelin, Dodge’s Challenger T/A, and Plymouth’s AAR ’Cuda in ’70 – but none would have the lasting impact that Z/28 did. Even if the original Z/28 had (figuratively) crashed and burned on track, its existence as the first street car built to satisfy SCCA Trans-Am rules would have been enough. That it dominated two of its first three years of existence? That its sales numbers increased massively year-on-year? That it put paid to the notion that small engines couldn’t be big-block-rivaling powerhouses, and that Americans didn’t care about cars that could handle and corner? Why, that’s just another swig of champagne in the winner’s circle.

Z28, Z-28, or Z/28? Well, Yes.

1969 Chevrolet Camaro Z/28 – Headlight/badge close-up

You may have noticed through the years of reading HMM that we don’t seem to use the Z28 name with consistent “style,” but that’s for a reason. Our practice is to mirror the nomenclature and style that the original manufacturer used for its vehicles, but in the case of the Special Performance Package Camaro, that wasn’t always the same. Chevy’s first-gen Trans-Am special Camaros were badged as Z/28 for ’68 and ’69, with a slash between the Z and the 2, but what about 1967? There was no badging, no advertising, and no appearance in the Chevy catalog. The Special Performance Package name appears as code Z28, as any other option code in a list that includes an M21 four-speed transmission or an L78 engine. No slashes. Period magazines, meanwhile, hyphenated the Z-28 in both headlines and print for ’67 (and even into ’68, as was the case with Road & Track). Car and Driver hyphenated for ’67 and used the slash for ’68. When the second-generation version of the package was revealed, it was shown as Z28, even on the badging. So, what may appear inconsistent on our part is simply an attempt to follow what Chevrolet did through the years.