1970 Buick GS 455 Stage 1 Convertible

Description

Raleigh Classic Car Auctions have built a pristine reputation over 26 years of live auctions, as the go-to for the best-of-the-best offerings for car collectors and enthusiasts. Regionally trusted and nationally recognized, Raleigh Classic Car Auctions continues to find low-mile, original examples with documentation annually. The October Special is an offering of 28 premium quality, low-mile and desirable, domestic lots from three private estates. All vehicles are available for in-person inspection at The Raleigh Classic Showroom in Zebulon, NC; 9:00am-4:00pm Monday-Friday: 10/28/25 - 11/12/25 or by appointment.

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The words “quickest muscle car” and “Buick” didn’t go together until 1970, when Motor Trend tested a GS455 Stage 1. The Skylark-based GS — with an automatic, a soft suspension, and comfortable seats — flew through the quarter mile in an astonishing 13.3 seconds at 105 mph, officially 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 “regular” GS455 was rated at 350 horses and a neck-snapping 510 pound-feet of torque. And selecting the Stage 1 package added high-performance upgrades like higher-flowing heads, an aggressive camshaft, and higher numerical gears, resulting in a laughably underrated 360 horses and 510 pound-feet of twist.  

And if ruling the streets in comfort wasn’t cool enough, Buick even built 232 GS455 Stage 1 convertibles that year. According to the selling dealer, this Sloan-documented 1970 GS455 Stage 1 is one of only two triple-black automatic-equipped convertibles said to exist. It underwent a documented two-year restoration, the date code-correct 455 was rebuilt and dyno tested, and the Turbo Hydramatic was rebuilt to survive behind one of the muscle car era’s greatest engines.”  

Highlights   

• Offered from The Raleigh Classic Collection  

• 7,959 miles indicated  

  • Based on the seller's thorough assessment, known history, and accompanying documentation, the odometer reading of this Buick GS is believed to be correct since restoration. 

• Rebuilt 455 cu-in Buick V8 dyno tested at 400 hp and 507 lb-ft of torque  

• Rebuilt 3-speed Turbo Hydramatic automatic transmission  

• Finished in (19) Regal Black with (TR 188) Black interior  

• Black convertible top  

• Air conditioning  

• The chassis number (446670H128686) decodes as:  

  • 4 – Buick   

  • 46 – GS455  

  • 67 – 2-door convertible   

  • 0 – 1970   

  • H – Flint, Michigan assembly plant  

  • 128686 – Sequential production number    

• The trim tag decodes as:  

  • 70 44667 - 1970 model year; Buick GS (Gran Sport) convertible (Fisher style 44667)  

  • FL1 05993 BDY - Flint, MI Fisher Body plant; body number 05993  

  • TR 188 - Black vinyl interior (bucket-seat trim) 

  • 19 B PNT - Paint code 19 = Black exterior; top code B = Black convertible top  

  • 09C - Fisher build date: 3rd week of September (’69) 

Features  

• GS455 Stage 1 package includes:  

• Special heads with 2.12-inch intake/1.75-inch exhaust valves and stiffer valve springs   

• Special hydraulic cam with 326º/346º duration and .490-inch lift  

• Richer carburetor calibration  

• Recalibrated ignition timing  

• Increased oil pressure  

• Larger cross-flow radiator  

• Aggressive calibration for auto trans-equipped cars  

• 3.42 gear ratio with a limited-slip differential (non-A/C cars got 3.64 gears)  

• Chrome valve covers and Stage 1 air cleaner decal  

• Exterior Stage 1 badges    

• 15-inch wheels wearing 235/60R15 BF Goodrich raised white letter tires (DOT 2017) 

• 10-bolt rear end   

• 2.25-inch high flow dual exhaust system  

• Power windows  

• Bucket seats with console  

• Tilt steering column with cruise control  

• Optional cluster with 120-mph speedometer, 6,000-rpm tachometer, oil pressure, coolant temp, and fuel level gauges  

• AM/FM/8 Track radio  

• Cold-air intake with hood-mounted scoops  

Known Imperfections   

• As with any vintage vehicle, some imperfections may be present. Interested parties are encouraged to review the photo gallery and contact the seller with any questions.  

Included Items

• Owner’s manual  

• Sloan report  

• Restoration receipts  

Ownership History   

This 1970 Buick GS455 Stage 1 Convertible is offered from The Raleigh Classic Collection with a clean California title. The seller notes, “since being acquired by the current owner 8 years ago, the GS has been meticulously maintained as a dependable driver with fully functioning heat, AC, radio, & convertible top. It has also been tuned for 93 octane fuel.”