Lovers of America's Only True Sports Car speak their own language, complete with alphanumeric shorthand for their Vettes' features. So did Chevrolet, when it came to describing the "racing" C3s.

With a GM-wide ban on all racing activities in force since early 1963, "special heavy-duty" and "special high-performance" hardware and vehicles came not from a Motorsports or Racing department within Chevrolet, but from its Product Promotion Engineering office.

And when it came to the highest-performance third-generation Vettes, this group came up with the Special Purpose Engine Packages, known by their RPO codes: ZR-1 and ZR-2.

Offered only in 1970, 1971, and 1972, the ZR-1 package featured the highest-performance small-block available-the new-for-'70, 370hp LT-1. (ZR-2 was originally to include the new, 465hp LS7 big-block, but that engine was never installed in a production Vette, though it was available as a crate engine. The ZR-2 did appear on the Corvette option list in '71, albeit in LS6 form. Confused yet?)

The package also included a Muncie M22 "Rock Crusher" four-speed, along with special heavy-duty suspension, brake, and cooling hardware. Not available were air conditioning, automatic transmissions, radios, power steering, or full wheel covers. If you wanted luxury, went the thinking, you could always buy a Cadillac.

Though Chevrolet didn't advertise these special option groups, word quickly spread among knowing Vette lovers, and a total of 53 ZR-1s were built between January 1970 and July 1972. (Add in 12 LS6-powered '71 ZR-2s, and the Special Purpose sharks total 65, in all.)

One Vette aficionado, Ed Foss, has owned nearly a third of the total ZR-1 output, including these two-the first and the last ZR-1s. "Back in the early '90s, I went out and hunted down all these ZR-1s," he says. "Within about three or four years, I had 14 of them. In the process, I found the pilot car, the very first one, and I got the very last one." He adds, "I also have the first '71 ZR-1."

The Monza Red '70 convertible seen here is that pilot ZR-1, in which St. Louis Assembly first combined the 370-horse LT-1 engine with the existing L88 heavy-duty chassis, powertrain, and suspension. When Foss found it, it hadn't suffered the fate of too many rare-optioned Corvettes. "That car had the original engine in it, and it was pretty much intact," he recalls. "When I got it, it had the original ragtop on it."

All original, yes-but not in good shape. Enter Paul Schuster, whose Damascus, Ohio, shop brought it back to factory-fresh condition with a one-and-a-half-year total restoration.

In better condition when he found it was the last-of-the-line '72 ZR-1 coupe. Since his purchase, Foss has only had a new coat of Pewter Silver acrylic lacquer sprayed on, by Gary Bossleman.

Both cars are multiple award winners, including Bloomington Gold, NCRS Top Flight, and Triple Diamond honors. Neither was road raced way back when, says Foss, though both "…competed in autocrosses around the country." He adds that a good number of his other ZR-1s were put through their paces that way. "Out of those 14 ZR-1 cars that I owned, about a third of them were autocrossed back in the day."

Foss has also been fortunate to meet up with both cars' original owners along the way. He met the '70's first owner at Carlisle, and the '72's original buyer-as it turned out-lived just down the road from him, and autocrossed the car in Indiana and Michigan many years ago. "I live near Fort Wayne, and that car, back in the '70s, was really close to me," says Foss. "I see him once in a while around the area."

If you're interested in adding an original ZR-1 to your collection, good luck. As mentioned above, only 53 C3 ZR-1s were ever made-25 in '70, 8 in '71, and 20 in '72. But if you're looking to go the "tribute" route and build your own, Foss says, "It's really about the engine and suspension. It's a small-block L88. If you follow the L88 ‘pattern,' and [have] an LT-1 engine, you're good to go."

As long as you enjoy the factory LT-1/M22 "sound system," instead of a radio.

'70 ZR-1 CONVERTIBLE
OWNER Ed Foss; Roanoke, IN
BLOCK Stock LT-1 cast-iron (casting #3970010 with "CTV" suffix)
DISPLACEMENT 350 ci
HEADS Stock LT-1 cast-iron (casting #39277186)
VALVES Stock 2.02/1.60
CAMSHAFT Stock LT-1 solid lifter
PISTONS Stock forged aluminum
COMPRESSION 11:1
CRANKSHAFT Stock forged steel
RODS Stock forged steel
INTAKE MANIFOLD Stock high-rise castaluminum (PN 3972110)
CARBURETOR Stock Holley 800-cfm four-barrel (PN 4489A)
FUEL PUMP Stock GM-Rochester mechanical
IGNITION Stock GM-Delco transistorized with Delco distributor (PN 1111491)
EXHAUST SYSTEM Stock '71 LT-1 with castiron exhaust manifolds, 2.5-in pipes, and OEM mufflers
TRANSMISSION Stock Muncie M22 heavy-duty, close-ratio four-speed manual
CLUTCH RPO MA6 heavy-duty
DRIVESHAFT Stock
SUSPENSION Stock Corvette ZR-1/RPO F41
BRAKES Stock ZR-1 heavy-duty four-wheel discs (RPO J56) with power assist
WHEELS Stock 15x8 steel Rally with chrome center caps and trim rings
TIRES Firestone Wide Oval Super Sport whitewall bias ply, F70/15
CURRENT MILEAGE Approximately 32,000

'72 ZR-1 COUPE
BLOCK Stock LT-1 cast-iron (casting #3970014 with "CKZ" suffix)
DISPLACEMENT 350 ci
HEADS Stock LT-1 cast-iron (casting #39278916)
VALVES Stock 2.02/1.60
CAMSHAFT Stock LT-1 solid lifter
PISTONS Stock forged aluminum
COMPRESSION 9:1
CRANKSHAFT Stock forged steel RODS Stock forged steel
INTAKE MANIFOLD Stock high-rise cast-aluminum (PN 3959894)
CARBURETOR Stock Holley 800-cfm four-barrel (PN R6239A)
FUEL PUMP Stock GM-Rochester mechanical
IGNITION Stock GM-Delco transistorized with Delco distributor (PN 1112101)
EXHAUST SYSTEM Stock '72 LT-1 with cast-iron exhaust manifolds. 2.5-in pipes, and OEM mufflers
TRANSMISSION Stock Muncie M22 heavy-duty, close ratio four-speed manual
CLUTCH RPO MA6 heavy-duty
DRIVESHAFT Stock
SUSPENSION Stock Corvette ZR-1/ RPO F41
BRAKES Stock ZR-1 heavy-duty four-wheel discs (RPO J56) with power assist
WHEELS Stock 15x8 steel Rally with chrome center caps and trim rings
TIRES Goodyear blackwall bias ply, F70/15
CURRENT MILEAGE Approximately 24,000