When GM decided to throw a curve ball at itself and pulled from all competitive racing in 1963, it made a lot of people shake their heads in disappointment.
But when the corporation also banned its division from putting some real muscle down on the street for the average Joe to enjoy, it downright committed a sacrilege.
Basically, no General Motors product was allowed to be an all-out street fighter, and the largest carmaker in the world even capped engine displacement allowance for the mid-size class.
Pontiac snapped first and released the GTO, furiously defending its track-earned medals. Chevrolet waited for a while, half-sedated by the fact that its Corvette was immune to the general curfew.
That’s how America’s sportscar was allowed to bear a big-block that surpassed the 400-cube limit imposed on anything less than full-size automobiles.
That’s also why the multiple carburation setup was forbidden to everyone except the Corvette. That’s also the reason behind the monstrously performant L88 from 1967-1969 and the LS7 from 1970.
Sidenote: the LS7 was planned but never executed. It should have offered 460 horsepower right off the showroom floor.
Still, it was considered too radical and canceled at the last moment, rather than after the last moment, as the sales literature was printed with the cataclysmic option among the power teams.
A long union strike delayed the debut of the 1970 model year by several months—enough to force General Motors brass hats into drastic measures.
The Camaro almost got canceled, and all the divisions reported massive drops in sales at the end of 1970. However, Chevrolet bosses had enough clarity in their decisions to keep one of the most amazing projects alive: the ZR1 Regular Production Option.
Seeing how the 454-cubic-inch plan didn’t go as initially devised, with the LS7 terminated prematurely, the Corvette had an ace up its sleeve: a heavy-punching small-block.
The LT-1 engine was based on the famous 350-cube V8, the notorious 5.7-liter small-block introduced in 1967, with massive doses of inspiration drawn from the L-88 and ZL-1 atrocities from 1969.
The 350-cubic-inch V8 was the same small-block released in 1967 on the first-gen Camaro SS, but in 1970, it got a few tweaks and twists.
Solid lifters, forged aluminum pistons, 11.0:1 compression, a four-bolt-mains forged steel crankshaft, a special high-lift camshaft, and a high-rise aluminum intake under the wide-gaping 780 CFM Holley four-barrel carburetor.
Add the baffled oil pan, the ram horn exhaust manifolds, high-volume pumps for oil and fuel (with no return line on the latter), a larger radiator and fan shroud, 2.5-inch (64-mm) exhaust, and transistor ignition. It was a neat motor that reminded gearheads of the 1965 350-cube fuel-injected V8 and its 375-horse output.
The C3 Corvette deserved a hard-hitting small-block of its own. Zora Duntov, the mechanical demigod from Chevrolet, had never laid down its wrenches in the face of corporate foot-in-mouth strategies.
The LT-1 was devised as the ultimate solution for racing over curves in an effort to get the sporty image redemption the Corvette needed after its big-blocks had creased it with their heft.
Essentially, the LT-1 engine was a lightweight, world-class puncher that could corner properly, unlike the 396 and 427 behemoths that laid down the sledgehammer furiously in a straight line but were punished severely around corners.
The heavy lump of iron over the nose took a heavy tool on handling. The small-block and its 370-horse output took care of that problem.
But Zora Duntov didn’t simply release a new engine onto the streets; he was methodical and devised a special package to accompany that engine into battle.
The Special Purpose Engine Package included several amenities – all mechanical: a close-ratio four-speed manual transmission (the famous Muncie M22 Rock Crusher), a heavy-duty starter, a lightweight flywheel, heavy-duty brakes, transistorized ignition, an aluminum radiator with a surge tank and metal fan shroud, heavy-duty springs and shock absorbers, and huskier front and rear sway bars.
Only 25 Corvettes with the ZR1 package were assembled in 1970, followed by eight in 1971 and twenty in 1972, the final year for the high-performance moniker.
Eight of the initial 25 examples produced during the short 1970 model year were convertibles. This number is lower than that of ragtop Hemicudas or Challengers, for example. So, any of those rare gems still around today is worth big money.
At least, that’s what sellers hope, and we’re three weeks away from finding out if half a million dollars for a restored 1970 Chevrolet Corvette ZR1 is a correct estimation. Not just any example, but the first one ever built.
The pilot car is a red convertible with only 31 miles (50 km) on the clock after a full renovation. Note that in 2011, the car showed 88,000 miles / 141,622 km on the clock (it was unrestored at the time).
The inceptor of the ZR1 legend will go under the hammer on January 17 at the Kissimmee car show and has an impeccable track record dating back to 1970, documentation included and dating back to 1970.
The car comes with a letter of recommendation from the National Corvette Restorers Society: a trio of Bloomington Gold certification and NCRS Chapter, Regional, and National Top Flight awards.
The engine, transmission, and 3.70 Posi rear are original equipment, backed by a Protect-O-Plate warranty card, a tank sticker listing the original features and options, and the signature of Chevrolet’s legendary chief engineer Zora Arkus-Duntov on the chromed air cleaner.
