THE LEGENDARY ZL-1

The 1969 Chevrolet ZL-1 Corvette enjoys a mythical status among production Corvettes.

The selection of the RPO ZL-1 option more than doubled the price of a new Corvette, and for that amount the buyer received a 560-horsepower derivative of the all-aluminum CanAm racing engine delivered in a street-legal, factory-built production car.

GM documents on file verify that only two so-equipped cars were produced at the St. Louis assembly plant and delivered through their dealer network. The 1969 RPO ZL-1 was strictly developed as an FIA/NHRA homologation experiment and, in practice, never truly intended for sale to the public.

And yet, on the chilly afternoon of 30 December 1968—John W. Maher of Leechburg, Pennsylvania arrived at Harold Breman’s West Penn Garage, tossed the keys to his trade-in (a 1968 L88 Corvette Convertible), and finished up the purchase paperwork for chassis 194679S710209, the first of these two factory-documented ZL-1 Corvettes. It is the only ZL-1 Convertible built, and—thanks to Maher’s influential friends—the only such Corvette ever sold new to a retail customer.

THE ZL-1: A MONSTER IS BORN

At the heart of the ZL-1 is a lightweight refinement of Chevrolet’s 427-cubic-inch L88 V-8 engine. Featuring an all-aluminum block, stouter connecting rods, a redesigned crankshaft, pistons, larger exhaust valves, a high-lift camshaft, and an upgraded “open chamber” aluminum cylinder-head design with four additional head bolts, the ZL-1 was the most powerful engine Chevrolet had yet created.

Importantly, the “open chamber” head design was not finalized until March 1969, and so the pre-production version of this engine—as originally fitted to 710209—retains “closed chamber” aluminum heads.

Having to first select the $1,032 RPO L88 before adding the $3,000 RPO ZL-1, power-assisted, heavy-duty brakes came standard, as did the heavy-duty suspension package, a Positraction rear axle, and transistorized ignition. The list of what you didn’t get was equally impressive: radio, heater, air conditioning, power windows, and power steering. Even the fan shroud was omitted because it interrupted airflow. At $4,718, the outrageous supplementary price of the all-aluminum ZL-1 package and its required speed accoutrements more than doubled the base price of a new Corvette.

RACER MAHER

During the summer of 1968, Maher’s close friend Don Yenko regaled him about an experimental, all-aluminum racing engine for the 1969 Corvette. The real kicker for a hardcore racer like Maher was that this new engine could be had with the M40 automatic transmission, perfect for clutch dumps and full-throttle launches.

After much difficulty, Maher was only able to secure his order with assistance from Grady Davis, a two-time SCCA national champion and senior vice president at Gulf Research, then a secret partner to GM’s clandestine racing operations.

Accompanying documentation from GM archives shows that on 21 November 1968, the ZL-1/M40 powertrain configuration was approved for production. The very next day, Maher’s order (AVM236) for a Monaco Orange ZL-1/M40 Convertible (710209) was accepted. The car’s Monaco Orange color was specified as thanks for Davis’s help, and this homage to his friend’s employer would continue throughout Maher’s ownership via the application of a Gulf Oil racing livery.

ASSEMBLY AND EARLY LIFE OF THE ZL-1 CONVERTIBLE

A complete trove of GM documents exhaustively illustrates that the entire process of production for 710209’s major components and final assembly at the St. Louis plant in December 1968 was immediately preceded at all stages by a parallel chain of internal memos, synchronized approvals, and engineering change recommendations which allowed Maher’s unique order to be fulfilled.

The effective dates of several of these files is 9 December, the exact assembly date on 710209’s trim tag. Along with Maher’s original invoice, tank sticker, and historic imagery, the high-quality scans of all relevant GM paperwork for this factory-built ZL-1 are on file and available for review by registered bidders.

Chassis 710209’s original engine was assembled on 22 October, paired with the transmission after 29 November, and then installed in Maher’s car on 9 December. An accompanying NCRS Shipping Report shows that just 24 hours later, Maher’s one-off convertible was ready for transit to West Penn Garage.

Drag racing modifications were immediately underway, as the car’s original sales invoice notes the installation of a pair of free-breathing side-pipes and a spare 4.11:1 rear end. Another interesting set of GM internal documents on file show that in January 1969 a service bulletin was sent to the originating dealer, requiring installation of a fan shroud (with clutch) into Maher’s ZL-1 on account of overheating issues first noticed on L88/M40-equipped customer cars.

From February 1969 until November 1972, Maher and this extreme Corvette terrorized hill climbs, autocross events, and drag races across Western Pennsylvania. Because of its M40 transmission, Maher labeled his ZL-1 with the cheeky moniker “Winning Automatically.” By September 1969, the car’s original short-block assembly had been blown and was replaced by another short-block assembly furnished under warranty by Chevrolet.

SINCE 1989

In 1989, Maher pulled the dormant ZL-1 out of hibernation, intent upon returning to competition. That task was entrusted to Bill Andrejko Auto Restorations of McKeesport, Pennsylvania, and the result of their excellent work was subsequently unveiled during the 1991 National Corvette Homecoming in Bowling Green, Kentucky.

Over the next 15 years, Maher undertook a regimen of exhibition and competition that would see this stellar machine claim awards at many of the nation’s most important Corvette concours and racing events, including Chip Miller’s Corvettes at Carlisle, as well as NCRS National Conventions in Charlotte, Orlando, Monterey, and St. Louis.

In 2007, Maher finally sold this ZL-1 to the consignor. After 39 years spent with its original owner, the car was surely due for a well-attended debut with its new custodian, and so the pair’s first exhibition together came during the 2008 edition of The Quail, A Motorsports Gathering.

With Bloomington Gold certification in his sights, by 2012 the consignor had submitted 710209 to Kevin Mackay’s Corvette Repair Inc., of Valley Stream, New York, widely hailed as the world’s foremost restorer of historically significant Corvettes.

Upon disassembly, Mackay and his staff found the car to be remarkably well preserved, and it quickly became evident that its blown engine was thankfully the only damage it had sustained during its racing career. Though not the original unit, the engine currently residing in the car is an extremely early, factory-correct, date-coded, all-aluminum ZL-1 unit.

Refinished in its factory-correct Monaco Orange paint and black vinyl interior, Mackay completed the car in time for the 2014 Bloomington Gold show in Champaign, Illinois. After much scrutinous review of its comprehensive factory documentation, 710209 was awarded Bloomington Gold certification and formally recognized as the first of the two factory-built ZL-1 Corvettes. Now conclusively recognized as “the real deal,” the car has also been a welcome guest at the Glenmoor Gathering, Radnor Hunt Concours, Pinehurst Concours, and special Bloomington Gold exhibits at Charlotte, North Carolina, and Indianapolis Motor Speedway.

In 2018, this ZL-1 Convertible was loaned to the prestigious and internationally acclaimed Simeone Foundation Automotive Museum in Philadelphia, Pennsylvania, remaining on display there until very recently.

Wearing an accurate, award-winning restoration from the most highly regarded restorer of historically significant Corvettes, 710209’s exceptional provenance is matched by its incredible performance and unique specifications. Thanks to its extensive factory documentation on file, this is, rather irrefutably, the finest and most unique special-interest production Corvette.

This opportunity represents the first time that a factory ZL-1 has been offered publicly in 30 years and, more importantly, the first time that the ZL-1 Convertible has ever been offered publicly.

This legendary creation offers a truly unrepeatable, once-in-a-lifetime chance to secure the ultimate keystone to any reference-grade collection containing significant examples of “America’s Sports Car.”