Patterned after the “Mako Shark II” concept and produced from 1968 to 1982, the third generation of Chevy’s iconic sports car series has by far the most aggressive and over-the-top design of all Corvettes. And at least up unit the 1973 oil crisis, it had the power to match its brawny looks.

But for an owner of a 1971 Corvette Convertible, the stock V8 wasn’t enough so he fitted the open-top model with GM’s LS9 crate motor, which is the same 6.2-liter supercharged V8 found in the most powerful series production Corvette of all time, the ZR1.

GM states that the crate engine delivers 638-horses at 6,500 rpm and a peak torque of 604 lb.-ft. at 3,800 rpm. The owner of the car said it made 536 rear-wheel-horsepower through an automatic transmission.

The C3 Convertible was built by Fastlane in Houston and also features upgraded brakes and suspension, along with power seats sourced from the ZR1. A cool touch is the ZR1-like window on the hood that allows the intercooler to be viewable from the outside.

LS9 specs

Displacement: 6.2L (376 cubic inches)Bore x stroke: 4.125 x 3.620 inchesCrankshaft: forged steelConnecting rods: forged titaniumCylinder heads: roto-cast aluminumValves: 2.16-inch titanium, intake; 1.59-inch sodium-filled, exhaustInduction: superchargedCompression ratio: 9.1:1Horsepower: 638 @ 6,500 rpmTorque: 604 lb.-ft. @ 3,800 rpm

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