Dyno Blast: 1969 Corvette L71 427 Rebuild in Action

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A stock-looking 1969 Corvette L71 427 makes better-than-stock power with a good rebuild.

This week’s Dyno Blast features a L71 big block from a 1969 Chevrolet Corvette undergoing some dyno testing – without the car. As you can see in the image above and the video below, this 1969 427 cubic inch big block V8 is on an engine dyno stand rather than being tested in a car. A bit unusual from our normal dyno videos featuring a car in action on the rollers.

The advantage of this method is that we get the actual engine horsepower rather than wheel horsepower and an estimated bhp figure, so when this L71 427 is plugged back into the 1969 Corvette – the owner will know exactly how much power is being channeled through the transmission.

Those of you who are familiar with the 1969 Corvette with the L71 engine package will notice that the engine being tested here looks relatively stock. It has the stock exhaust manifolds, the stock intake manifold and the stock air cleaner design – presumably hiding a stock (or near-stock) “Tri-Power” carburation setup with a trio of 2-barrel carbs. However, don’t let the stock manifolds and stock air cleaner fool you, as this Chevy big block was rebuilt to perform better than stock while looking like a factory stock engine.

ls1tech.com dyno blast 1969 Corvette L71 427 rebuild 500hp

The 1969 Corvette with the L71 427 V8 offered 435 horsepower at 5,800rpm and 460lb-ft of torque at 4,000rpm when it rolled off of the Bowling Green Assembly Line. Thanks to the folks at CPMotorworks Inc of Janesville Wisconsin, the output of this stock-looking 427 has been increased from 435 horsepower to 500.5 horsepower at 6,000rpm while torque levels are increased from 460 to 479.5lb-ft.

Of course, we don’t know what changes have been made inside of this 1969 L71 427, but this video shows that a good rebuild of a classic engine can add power to your old V8 without changing the appearance of the engine.

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