General Motors Unleashed Tripower 427 Corvette.

This is one of the most sought-after Corvettes ever built. What you are looking at is a 1967 427 Tripower Corvette, the L71-optioned beast. There are, of course, a few sought-after ’Vettes: a 1963 Split rear window Corvette, a 1967 427 L88 optioned ’Vette or even the 1953 ’Vette, the first model released. To figure out how the hell Chevrolet came to be selling such a wickedly potent beast, we have to step back a bit in time. In 1953, Harley J. Earl, Director of General Motors Design, caused the first ’Vette to come into being. Originally released at the 1953 Motorama, the media got its first look on January 16th, a day before the show started. It was estimated that 4 million people got to see that first Corvette and the public response was overwhelmingly positive. It was a huge shift for Chevrolet to be producing a Fibreglass-bodied sports car. It was powered by a 6-cylinder engine and had a Powerglide transmission. There were early setbacks to the ’Vette, and there were probably times when the ’Vette’s future was in doubt, but Harley Earl and his crew continued on. The shape of the first ’Vette went through three body changes during its 10-year life. It gained V8 motivation and the Corvette Chief Engineer Zora Arkus-Duntov improved many of the car’s traits, including independent rear suspension.

In 1958, following Earl’s retirement, Bill Mitchell took over the GM design team. Mitchell had purchased a mule chassis that Duntov had done a lot development on; it was developed for the 1957 Corvette SS raced at Sebring that year. Mitchell took this chassis to his ‘Studio X’ special projects area. He and some of his friends financed the development of a racing car that was called the Sting Ray Special. When you see a picture of it, it’s a dead ringer for the 1963 Corvette Sting Ray. Bill entered this car as a private entry into the SCCA C-Modified championship. It never appeared with the Corvette name or ran with any backing from GM. Larry Shinoda refined the Sting Ray Special’s shape to create the 1957 XP 755 Shark show car. Not many of the Shark’s design features were carried over into the 1958-1962 ’Vettes, maybe the ducktail rear end of the 1961 ’Vette, but that was about it. Come 1963 and the styling cues from that Shark show car manifested in the shape of the brutally muscular Sting Ray. Mitchell’s Corvette had arrived.

BIG NUMBERS

The 1962 Corvette sold the biggest numbers of any year’s production so far; 14,531 ’Vettes were built in ’62 year and GM was happy with that. In 1963, 21,513 ’Vettes were built. The Sting Ray was a huge success and GM ecstatic; Mitchell’s status was immediately elevated to one of GM’s favoured sons.

For the first time ’Vettes were available as either convertibles or coupes, and the new coupe sold almost as well as the convertible. Back in 1953, one of the show cars that came out with the new Corvette was a coupe version called the Corvair. It never saw production, which was a crying shame because it was a beautiful design; but 10,793 coupes were built and 10,919 convertibles hit the road in ’63. Duntov fought and won for the Sting Ray to have independent suspension front and rear. The old X frame chassis was gone and a much better ladder frame chassis was now under the ’Vette. The ’63 ’Vette coupe had a split rear window, a styling feature Mitchell insisted upon. If your uncle has got one of these rotting in a shed, go right now and offer him a couple of hundred notes for it and restore it immediately. Coupes only had split rear windows in 1963, which now makes them hugely valuable.

The 1964 ’Vette lost it, and many of the ’63 coupe owners removed the split window in favour of the new one-piece window¦ sigh. Until 1965, the Sting Ray ’Vettes only came with 327 cui V8s; fuel injection was an option to get more power − 360hp over the 4-barrel carb’s 300hp. In ’65, the Corvette was offered with the Big Block 396cui V8; the muscle car era was starting to take hold. GM had a rule that their small cars weren’t to come out with any motor bigger than 400cui. That 396cui was developing 425hp, which hurled the ’Vette down the road at a huge rate of knots. It did the quarter mile in just over 14 seconds and it got to 60 mph in 5.7 seconds. Please remember this is a factory standard car. In 1965¦ By 1966, GM broke its golden rule and wedged a 427cui under the hood of the ’Vette, still only pumping out 425hp (only! Though in reality, the 427cui was pumping out 450hp but the GM gods downgraded it to 425hp¦whatever).

The ’Vette was nonetheless into the future. Drivers for Sports Car Graphic magazine got hold of a ’66 427 Vette equipped with a 4.11:1 diff and managed to do 0-60mph in 4.8 seconds, 0-100mph in 11.2 seconds and attained a top speed of 140mph. Ladies and gentlemen, 1966 was a fine year for the US of A.

MORE STING RAY

In 1967 there was supposed to be a brand new model of Corvette released, but Duntov was not entirely happy with some of the nasty aerodynamic issues in the new shape, and so the Sting Ray remained for another year of production. This year saw the shape of the Sting Ray become simplified, with the removal of the fake vents and emblems. The interior received different upholstery and the handbrake was repositioned. Under the hood some radical changes took place.

The 427 now came in three new configurations: triple 2 barrel Holley carbs pumping out 400hp called the L68; the one you see on the pages before you, with 435hp using Triple 2 barrel Holleys, 11:1 compression, solid lifters and a new transistorized ignition called the L71; the third 427 came with Aluminium heads, radical cam, 12.5:1 compression and a monstrous (for the time) 850cfm Holley 4 barrel carb, officially rated at a measly 430hp due to GM’s understating (though again, in reality more like 560hp). The quarter mile vanished in just over 13 seconds and the car reached 0-60mph in less than 5 seconds. Only 20 of these L88 Sting Rays were built and, at last count, only three of them were still known to exist. The number of ’Vettes built dipped in 1967 from 1966’s all-time high of 27,720 cars to just 22,940.

KIWI L71 BIG BLOCK VETTE

Billy Dunn new exactly which Corvette he wanted. No questions asked — nothing less than a 1967 Tripower 427cui Corvette Coupe would do. Billy has had a wicked list of cars in his few years on the planet. A 12-second B Street rod, two 11-second Altereds, and Peter Lodge’s 10.3-second Amco Fiat have all lived at Billy’s at one stage or another. Back in 1994, Billy’s dream car was an L88-powered ’Vette. These were, of course, seriously thin on the ground, and barkingly expensive, which meant that Billy went for the next best thing. He had a few people in the US looking for a Tripower for him. Mostly they just told him that what he wanted, he simply couldn’t get, because he didn’t have enough money.

Billy was patient, and in 1994 Kevin Ireland from the Corvette Connection of San Jose found this beauty at the Pamona show with a “for sale” sign on it. A phone call was made back to Billy in Godzone and the deal was done. Billy kissed his money goodbye and then had to sit back, be patient and wait. And wait. And wait. The money went through in late ’94 and Billy didn’t get to see the car until ’95. When it eventually arrived, Billy was absolutely ecstatic. He’d finally gotten his Tripower back to NZ. However it didn’t end up being registered till ’96; Billy had to get a lot of things fixed. Little things like sand in the headlight motors and sand all through the wiper motors.

ince Billy has had it road registered, it has clocked up the miles. And they haven’t all been easy miles, either. It’s been down the quarter mile in 13.182 seconds at 109.43mph. Such an awesome strip time came after a 4.11:1 diff was put in. Billy pointed out that the original 14-second quarters were done on cross ply tyres. Billy tried a 3.08:1 diff but while good for touring, it was horrible around town.

Owning such a beast of a car with this much history isn’t always a bed of roses. The Tripower triple carb setup is a pig to keep tuned, and because the carbs are sitting in the V of what is a very hot engine, the petrol boils in the carbs. Another issue plagued Billy for quite some time — the car had a nasty misfire. Billy and all of his cohorts couldn’t figure it out until the day came when they tried a new distributor cap. Turns out that the original factory dizzy cap was wired wrong and had a crossfire going on.

I went for a cruise with Billy in the ’Vette. What a dream, riding in a Tripower Corvette. The acceleration when Billy asked for it is just blistering; that 4.11:1 diff meant its “push-you-into-the-seat-factor” is huge. The smiles per mile factor is even bigger. The Saddle coloured interior is in immaculate condition, and while I’m held in place by the comfortable seats, my ears are ringing to the beastly sound coming out of the side pipes.

The exhaust was a factory option called “Off Road Pipes”. It is amazing to think that I was sitting in a completely original, factory optioned car dating from 1967. Mechanical Anger was the only way I could think of to describe this mountain of an engine wedged into this tiny body.

Billy shows the car the respect it needs: cruise it where appropriate, cane it hard wherever he can. It lives in a garage, but I wouldn’t call its life an easy one.

Cheers Billy.

SPECS 427 Vette

Engine: L71 427cui Big Block, 4 bolt mains, 11:1 compression, solid lifters, 3 x Holley 2 barrel carburetors, Transistorized Electronic Ignition, Off Road exhaust side pipes.

Drive train: 4 speed Muncie gearbox, Positraction LSD, 4.11:1 10-bolt diff.

Brakes: Special heavy duty brakes. Discs all round with 4 pot calipers.

Wheels and Tyres: 15 x 6 Rallye rims with 205/75/15s all round.

Paint: Goodwood Green.

Sounds: Factory AM/FM radio.

Performance: Quarter mile 13.182 seconds at 109.43mph, 60ft time 2.071 seconds. Billy has had this engine dyno’d at just under 500hp.

DRIVER PROFILE

Name: Billy Dunn

Age: Mind your own business.

Occupation: Retired from the Trucking Industry.

Previously owned vehicles: ’32 Roadster, ’68 Camaro RS, Amco Fiat, Two 11-second Altered drag cars and a 12-second B class street rod and¦ to many others to list.

Dream car: At present a 1970 Dodge Challenger with a 426 Hemi.

People to thank: Steve Noyer of Moselle Panel and Paint.