1972 Buick GS 455 Convertible

This 1972 Buick Gran Sport is a performance-built two-door convertible that has been driven just 2,500 miles since the installation of a $10,000 upgraded 455ci V8 backed by a rebuilt 3-speed TH350 automatic transmission. The seller has owned the vehicle for 11 years and oversaw the installation of the 510-horsepower drivetrain, which includes ceramic-coated headers, a 3” stainless-steel exhaust system, an aluminum intake, and more. The power-operated convertible top has been replaced and the stereo has been augmented by a modern glove box-mounted Kenwood AM/FM/CD head unit. Finished in red with a white convertible top over a white vinyl interior, this GS is now offered with the motor build sheet, service records, and clear New York title in the seller’s name.

First appearing in the mid-1960s, the Gran Sport (GS) name was applied to midsized Skylark models with high-performance optioning, sharing chassis architecture with sibling General Motors A-body cars but with specific drivetrain and aesthetic upgrades. This GS convertible from 1972 started out as a GS 350 and was subsequently upgraded, featuring a rust-free body that was repainted red and received a replacement white cloth power-retractable top, 455 badging to match the upgraded engine, and a dual exhaust system.

Aluminum 14” Magnum 500-style wheels are wrapped in newer 225/70 Turbo-Tech G/T Radial raised-white-letter tires, and handling is assisted by power steering and power brakes.

The interior is trimmed with original white vinyl bench upholstery that is free of rips, color-matched to the door panels and contrasted by a black dash and replacement carpeting. Amenities include woodgrain dash trim, a newer Kenwood AM/FM/CD stereo, and speakers in the kick panels. The sale includes a bracket for the air conditioning system but no A/C components are included or installed, and the trunk contains a spare tire.

Instrumentation is presented by a factory 120-mph speedometer, an analog clock, an aftermarket 8k-rpm tachometer, a fuel gauge, and additional under-dash readouts below the dash. The five-digit mechanical odometer reads 83k miles, although true mileage on the chassis is unknown.

The replacement 455ci V8 was rebuilt in 2011 and bored 0.40 over by BTR Performance Solutions, featuring high-power equipment such as an aluminum intake and heads, an 850-cfm Quick Fuel carburetor, ceramic-coated headers, and 3” stainless-steel exhaust system. The seller states that the powertrain in its current configuration has been dyno-tested and generates 510 horsepower and 600 lb-ft of torque. Power is fed to the rear wheels via a rebuilt 3-speed TH350 automatic transmission with a shift kit and a 3.08 positraction rear end.

Photos showing the underside are available in the carousel.

The sale includes service records, a motor build sheet, and the results of a 2011 dyno test.