The L88 Corvette burst onto the scene with victories at Daytona and Sebring in 1966 and continued at the Le Mans Trials in April 1967, where, in near-stock trim, an L88 clocked 171.5 mph on the Mulsanne Straight. That same car led the GT class in the 1967 24 Hours of Le Mans for 11 1/2 hours before throwing a (stock Chevy) rod. Jerry Thompson and Tony DeLorenzo dominated SCCA A Production in 1969, with eleven victories in as many starts, and though production ended in 1969, L88s dominated GT and A Production racing for the next decade.
After three years of watching the 427-ci Cobras run away from the Corvettes, Chief Engineer Zora Duntov designed the L88 as a Cobra killer. In 1966, Duntov took a NASCAR-developed 427-ci big block, dropped it into a Corvette coupe fitted with optional heavy-duty brakes and suspension, and turned it over to Roger Penske. At the 24 Hours of Daytona that year, Penske’s drivers, Dick Guldstrand, George Wintersteen, and Ben Moore, came home first in the GT class and 12th overall. At Sebring, the same team earned another GT class victory, finishing 9th overall in the 12-hour enduro. All this was a tune-up for the 24 Hours of Le Mans in 1967.
Based on the 1966 prototype, RPO L88 was quietly added to the 1967 Corvette option list. The L88 was not just an engine, but a complete package for FIA GT and SCCA A Production racing. To meet these rules, the L88 had to be factory-built and street legal, so it came straight off the St. Louis assembly line.
Everything a racer would need
The package included all the pieces a racer would need: F41 heavy-duty suspension, J56 heavy-duty brakes, Harrison aluminum radiator, and a special forced-air hood with raised “Power Bulge.” Deleted were all the items a racer would throw away, including radio, heater, air conditioning, power steering and power windows. Duntov also dispensed with the radiator fan shroud, since he found it restricted air flow above 80 mph. Standard transmission was the M22 “Rock Crusher” 4-speed, named after the sound of its straight-cut racing-grade gears. But the real legend was under the hood.
Built at the same Tonawanda, New York, plant that produced big-block engines for everything from C-10 pickups to Camaros and Corvettes, the L88 was blueprinted and assembled in a special room that Duntov called “surgically clean.” Only the best GM components were used, like aluminum cylinder heads with 2.19-inch intake and 1.84-inch exhaust valves, developed in the Can Am series. Forged pistons with 12.5:1 compression were fed by a massive 850-cfm Holley 4-barrel atop an aluminum manifold. The solid-lifter cam was a wild one, with 354-degree intake/360-degree exhaust duration and 0.540 inch lift on the intake, 0.560 inch on the exhaust. A lightweight flywheel and 10.5-inch clutch rounded out the drivetrain. With open exhaust, the L88 recorded 560 hp on the dyno, though the factory claimed 430 hp, five less than the street L71.
The L88 dominated racetracks. Though the ’67 Le Mans effort failed, Jerry Thompson, a GM dyno technician, and Tony DeLorenzo, the son of a GM executive, put their Owens-Corning L88s in the winner’s circle in every A Production race in 1969. In a cover story for Car Life magazine, Thompson and DeLorenzo said they drove stock L88s from the St. Louis plant to their Michigan shop, where they were blueprinted and prepared. Other famous L88 racers included Don Yenko and actor James Garner in the ’60s, and Dave Heinz, John Greenwood, and comedian Dick Smothers in the ’70s.
But none of the L88’s equipment is the kind a sensible person would want in a street car. In fact, in its test of every 1969 Corvette model available, Car Life magazine found the 435-hp L71 was actually faster in street trim than the L88. The stock exhaust was the culprit, of course, rendering the L88 over-carbureted and over-cammed. Without a fan shroud, the L88 often overheated in normal driving. It took a strong leg to operate the racing clutch, and heat from the mighty 427 filled the cockpit. That’s what happens when you try to drive a race car on the street. Duntov asked that somebody try to get his message across: “The L88 is being bought by people who don’t know or care to use it properly,” Car Life reported. “They hear it’s the hot thing to have, and that the factory doesn’t put L88 on the order blank, so they order one.” Like some forbidden fruit, many of the 216 L88s produced never saw a race track.
Buyer ignored Duntov’s warning
Bill Doskocz, Jr. ignored Duntov’s warnings and ordered this 1968 L88 for street use. Doskocz, of Orlando, Florida, recalled in a letter to the car’s second owner “The car was purchased from Harrison Chevrolet in Marianna, Florida, in late 1967, it was new and I have been the original and only owner… It was a very late 1968 Corvette. I ordered the L88 motor, special brakes, M22 transmission, off-road service exhaust, telescoping steering wheel, head rests, leather trim, special suspension….” He also ordered Medium Blue leather interior, transistor ignition, and 3.70:1 Positraction.
He continued, “I drove the car approx. one year and had a very bad back end wreck. This was fixed by Paul Van Zant in Tallahassee, FL, at a cost of approx. $2,500. At that time the rear end was customized and a blue Firemist paint job done. I then brought the car to Orlando, Florida, and drove it daily for almost 1 year before I parked it and let it set for approx 1 year. I then drove it for 6 to 8 months and parked it in late 1974 or early 1975 and left it until this sale today (March 22, 1980). The car is an original factory L88 and has the original brakes, block, heads, intake manifold, crank, rods, rear end, transmission, and I would estimate approx 90% of the other original major items on it… I never raced the car professionally and never took it to a drag strip for an official time. It has seen its share of street racing and I had much pleasure in going extremely fast in this car.” How fast? Bill Doskocz claimed over 140 mph, and we know other L88 owners who can match that.
When Karl Hallstrom bought the car from Bill Doskocz, he not only got a mostly original Corvette, but also the Owners Protection Plan with Protect-o-Plate, the carbon copy of the original order form, the actual window sticker, a copy of the original title, the dealer’s thank-you letter and even Chevrolet’s instructions on how to install a choke on the race-ready Holley. Soon after buying the L88, Hallstrom decided to return the body to its original state. He turned it over to Country Corvettes in Nortonville, Kansas, first for a repaint and later for a first-class restoration.
Hallstrom showed his L88 as part of the 1988 Bloomington Gold Special Collection as a restored, running and driving rolling chassis. After completion, the L88 earned a Top Flight award at the 1989 NCRS National Convention. It’s been invited back to the Bloomington Gold Special Collection two more times, and in 1999 earned the NCRS Duntov Award of Excellence. On August 25, 2004, it was sold to its third owner, where it remained until August 2007.