1967 Chevrolet Corvette Coupe - 1967 L88 - Uncovered!

Bill Tower's Gm Proving Grounds-Tested Legend

Cam Benty Mar 1, 2004 0 Comment(s)
Corp_0403_01_z 1967_chevrolet_corvette_coupe Left_side_view 1/13

On the outside, it looks like a stock '67 Corvette with a crazy-looking side pipe. But underhood, it's something special.

When you figure out just how many were built, the L88 option should have been a small footnote in Corvette history. In 1967, only 20 cars were equipped with this landmark option, most ending up in racing environments, never seeing local cruise nights or pleasure driving of any kind. Rarity, however, breeds interest; and, today, the more rare the musclecar, the more public excitement it generates.

The Bill Tower '67 L88 is unique among L88s. It was the General Motors Proving Grounds test car in 1967, and saw plenty of track time before it was shipped to Florida for resale at Rathman Chevrolet in Melbourne. It is an L88 with perhaps the most colorful history short of the L88 race cars that competed at Le Mans and Daytona that famous year. It is a true delivered-to-the-public L88, complete with all the original artifacts including some prototype side pipes, unique L88 sticker placements, and functional L88 stinger hood.

Frankly, we're quite proud to bring this L88 Corvette to the pages of Corvette Fever for a number of reasons. First and foremost, this rare Goodwood Green L88 hasn't been out of Bill's garage in five years, and he was kind enough to break it out and clean it up for our photo shoot. This is an amazing 500-plus-horsepower production car that represents a significant piece of Corvette history.

But Bill's stories were the best part of our encounter with the '67 L88. While he hadn't forgotten about the great mid-year stashed in his garage, seeing the car in the light of day brought back memories of when it was new and he worked at the GM Proving Grounds. At that time, for the most part, Bill was focused on solving the 435hp big-block's overheating problems. According to Bill, those cars wouldn't even idle for three minutes without going over 230 degrees and overheating. Bill helped fix many of those problems with a stiffer fan clutch, but they were always difficult to keep cool.

At a different location on the grounds, the L88 development team was hard at work building up this thinly disguised race car. Through the work of Marty Sullivan at Holley Performance Products, they developed the 850-cfm carburetor that was standard equipment on the engine and in future street machines around the world. During that time, Bill had a chance to witness the uncorked raw power of the L88 at speed. As Bill tells it, "When that L88 hit the high bank, everyone stopped what they were doing to watch."

Don't you wish you were there?

Chronology
The '67 L88 shown here went through some interesting hands before ending up in Bill Tower's garage. After its days of Proving Grounds tests, it was shipped to Indy 500 winner Jim Rathman at Rathman Chevrolet in Melbourne, Florida. The car was a present from General Motors to Bill for handling the delivery of the Corvettes Chevrolet gave to the NASA astronauts that year. In fact, the L88 and all of the new Corvettes for NASA were shipped on the same car carrier.

At the time, the L88 was damaged, having dropped a valve in the last of its Proving Grounds tests. The non-running L88 was on the top row of cars on the carrier, which made the unloading process interesting.

"I spoke with the guy who unloaded the car from the carrier that day," says Bill. "He said it was quite a 'ride,' as the car had the J56 metallic brakes and no engine power. As a result, the unheated brakes didn't hold; but, luckily, it stayed in the ramps when it literally bounced from the top row to the bottom. It could have been a complete disaster."

While the car was supposed to go directly to Rathman's home, it ended up going to the dealership for engine repairs. The head was removed and repaired, and no other internal engine damage was seen. Shortly thereafter, Rathman and his team took the car to nearby Daytona for some testing of their own.

At Daytona, they got the car up to 180 mph.

Corp_0403_05_z 1967_chevrolet_corvette_coupe Rear_view 5/13

By virtue of the higher-rate springs and shocks, the Sport Suspension package made these classic '67 Corvettes sit a bit lower over the suspension.

"At Daytona, they got the car up to 180 mph," says Bill. "She was really running hard and it must have been a pretty impressive time. But, somewhere along the line, they didn't let the tires cool down enough between runs or something, and the car blew the left rear tire. A chunk of the tire hung from the rim and tore up the fenderwell, including tearing off the fuel lines. The car caught fire and, while the damage wasn't extensive, it was hurt."

The car once again headed back to Rathman Chevrolet and the repairs were completed, returning it to original specs. Not long after, the car was sold to a local man who ran a dairy. He purchased it for his son and they drove it locally for a while. While they had the car, the engine spun a rod bearing and they replaced it with a different engine. When Bill purchased the car through another party, he wasn't certain of its history; he simply liked what he saw.

"I really didn't know if this was the car from the Proving Grounds until I spoke with Jim Rathman, who confirmed the background on the car," says Bill. "It was around 1971 or '72 when I bought the car, and back then no one cared about big-blocks. For most, they were a joke. I did locate the original engine in the hay barn where it had been left. The dairy farmer gave me the broken engine for free, and I returned it to original specs after a while. For a long time, the car just sat until I had time to work on it."

Unique Parts
The '67 L88 was a unique car for a number of reasons, not the least of which included the special headers that came inside the car when delivered. According to Bill, they were similar to the Grand Sport Corvette side pipes with a flattened underside to achieve better ground clearance. As the owner of Grand Sport No. 5 driven by Roger Penske, he should know. The water neck in the intake is a special design for the L88, which also had special 7-inch-wide wheels from Kelsey Hayes for better handling at high speed.

Says Bill, "The 7-inch wheels and Goodyear Wide Oval redline tires made a big difference in the handling of the car. The improvement from 6 to 7 inches is huge in terms of stability and overall handling. This, I believe, was the first year for the Wide Oval tires."

The radio- and heater-delete are specialty options that few Corvette owners ordered, for obvious reasons. A one-year mandate, the heater/defroster equipment returned in 1968 for L88 drivers as a matter of safety (the defroster option made them safer to drive in cold climates). Regardless, if you owned an L88 and needed a radio, you were in the wrong car.

Bill Tower's '67 figures to be one of the very first L88s ever created, due to its Proving Grounds lineage. While Bill never claims it is the first one, the experimental doorsill plate and history certainly give it that feel.

But what may be the best part of this story is that Bill is not afraid to drive the car today, although it has been in storage for so long. When challenged by a C5, he gladly accepts. After all, he has a legend to protect.

Chevrolet
0.0.XP - PROVA - 0001
194377 - 00 - IT - EX.702

0.0. = experimental Corvette
XP = experimental
PROVA = Proving Grounds
0001 = first prototype

19437 = coupe
7 = Year 1967
00 = Experimental Corvette
IT = Heavy-duty
EX.702 = last number in the ID plate

Corp_0403_09_z 1967_chevrolet_corvette_coupe Side_pipes 9/13

The side pipes for the L88 cars came in the interior of the car for later installation by the owner. They were unique because they were flat on the bottom for better ground clearance.

L88 Options
C48: Deletion Option for Heater and RadioA '67-model-year option incorporated to discourage street use and reduce overall vehicle weight by removing the heater and defroster. A radio could not be ordered with the L88 option.

J50/J56: Heavy-Duty Power-Brake Combination
A special proportioning valve that increased braking effect to the front to compensate for weight transfer under heavy braking. Brake shoes were stronger than stock units for improved retention. Famous dual-pin front brake calipers were used.

K66: Transistor Ignition
This was the standard transistorized ignition that was used on the L71- and L89-equipped Corvettes from '67 to '69.

F41: Special Suspension
Installed heavy-duty front coil springs and heavy-duty shocks both front and rear, and a heavy-duty seven-leaf rear spring.

M22: Close-Ratio Four-Speed Manual Transmission
Heavy-duty manual transmission with fine-spline input shaft, a large-diameter output shaft, and gear teeth that utilized reduced helix angles. Much noisier transmission than standard Muncie.

G81: Posi-traction Rear Axle
Standard production Corvette Posi-traction system

L88 Engine Tech Pointers:
* The '67 and '68 L88 engines used closed-chamber aluminum heads with a 12.5:1 compression ratio. A required sticker was placed in the interior of the car: "WARNING: Vehicle must operate on fuel having a minimum of 103 research octane and 95 motor octane or engine damage may result." According to Bill Tower, this sticker was supposed to be placed in the glovebox next to the tire-pressure sticker. Most are located behind the stick shifter on the console.

* The '67 L88 Corvettes came without emissions equipment. The '67 L88 Corvettes were equipped with a black road-draft tube mounted on the driver side of the engine. It was used to draft partially filtered gases out of the engine.

* The '67 L88 engines were more unique than later models because the valve covers, aluminum heads, and block were painted Chevy Orange. The '68 and '69 L88 aluminum heads were left bare and the valve covers were chrome.

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