40-Years-Owned, Modified 1970 Buick GS455 Sport Coupe

Description

The words “quickest muscle car ever” and “Buick” converged in 1970, when Motor Trend tested a GS455 Stage 1. The Skylark-based GS — with an automatic, a soft suspension, and comfortable seats — tore through the quarter mile in an astonishing 13.3 seconds at 105 mph, putting Hemis and LS6s on notice.

The secret lay in Buick’s expertise in building high-torque V8s. When GM’s ban on big-inch engines in intermediate cars expired in 1970, Buick built a high-compression 455 — and the results were spectacular: the base GS455 was rated at 350 horses and a neck-snapping 510 pound-feet of torque. And there was more: the factory Stage 1 package added higher-flowing heads, an aggressive camshaft, and higher numerical gears, resulting in a laughably underrated 360 horses and 510 pound-feet of twist.

Buick even built two Stage 2 prototypes, which improved the exhaust side of the engine: parts like new heads with two-inch exhaust ports, a revised cam, 11:1 compression, and headers were rumored to make 100 more horsepower — but the Stage 2 never saw production.

This sinister example is one of only 8,732 GS455 Coupes built in 1970. The seller purchased it in 1986, and after a reported restoration 20 years ago, it now represents what a factory Stage 2 build would have looked like. It has been refinished in black paint over black upholstery, with a Stage 2-style hood scoop. And the 455ci V8 was reportedly overhauled approximately 1,000 miles ago with a roller cam, ceramic-coated headers, and a three-inch exhaust system. That mill is backed by a three-speed Turbo Hydramatic transmission and a 4.10 positraction rear end.

This Stage 2-style 1970 Buick GS455 Sport Coupe is now offered with extra parts including a stock radio, a car cover, and a clean Arizona title in the seller's name.

Highlights

• Owned by the seller since 1986

• Legendary ’70 GS455 modified in the style of a Stage 2

• Finished in black with black upholstery

• Stage 2-style hood scoop

• Rebuilt and modified 455ci Buick V8

• 3-speed TH-400 automatic transmission with 4.10 posi rear end

• Front disc brakes

Factory Equipment

• Sport Coupe styling

• Perimeter frame

• Heavy duty coil springs and shocks

• Vinyl seats

• The chassis number (446370Z110156) decodes as:

  • 4 – Buick

  • 46 – GS455

  • 37 – 2-door coupe

  • 0 – 1970

  • Z – Fremont, California assembly plant

  • 110156 – Sequential production number

• The trim tag decodes as:

  • 70-44637 – 1970 Buick GS (Gran Sport) coupe

  • BF 00429 BDY – Fisher Body plant number 00429

  • TR 189 – Burnished Saddle vinyl bucket seats (now black)

  • 50 H PNT – Bamboo Cream paint (now black)

  • 12A – First week of December build date

Modifications

• Stage 2-style hood scoop

• 15” Centerline wheels with radial front, drag radial rear tires

• Buick rear window graphics

• Rebuilt 455ci V8 bored .030-over

• TA Performance Stage 2 aluminum cylinder heads

• Aftermarket air cleaner and TA Performance valve covers

• Double-pumper 4-barrel carburetor

• TA Performance SP Stage 2A aluminum intake manifold

• Roller camshaft

• MSD ignition system

• Ceramic-coated headers and 3” dual exhaust system

• Aftermarket rear lower control arms, sway bar, and double-adjustable shocks

• Replacement front shocks

• 12-bolt rear axle with 4.10:1 gearing, Strange Engineering axles, and C-clip eliminators

• Under-dash gauges

• Aftermarket AM/FM/cassette head unit

Known Imperfections

• Chassis and underbody rust

• Tire date codes are older

• Images detailing the condition of the 1970 Buick GS455 Coupe are presented in the gallery

Ownership History

From the seller, “20 year-old restoration, the body and chassis are completely original. Never saw any rain, only water from a hose. The engine has less than 1,000 miles on a fresh rebuild.”

Included Items

• Extra parts

• Stock radio

• Car cover