1968 Buick GS 400

Muscle car powered by 1968 Buick 400 four-barrel V8.

1968 Buick GS 400 convertible in a stock-appearing configuration; visible trim does not establish individual-car originality

Factory target 1968 Buick GS 400

Engine 400 cu in Buick V-8, factory-published 340 bhp

Torque 440 lb-ft at 3,200 rpm in Buick AMA specifications

Body styles 2-door hardtop coupe and convertible

Story

1968 Buick GS 400

Buick redesigned its intermediate line for 1968 and carried the GS 400 into the new body as a hardtop coupe or convertible. Its 400-cubic-inch V8 retained factory ratings of 340 horsepower at 5,000 rpm and 440 lb-ft at 3,200 rpm, giving Buick buyers big-block performance in a more restrained package.

Factory specifications list a synchronized three-speed manual, a four-speed manual, and the Super Turbine automatic. The Salisbury rear axle could be ordered with Positive Traction, while power brakes, front discs, Rallye wheels, bucket seats, consoles, and tilt steering were among the available equipment.

A GS badge is only a starting point when evaluating a car. The 44637 hardtop and 44667 convertible model references, vehicle data plates, drivetrain stamps, and supporting paperwork should agree. Factory records report 10,743 hardtops and 2,454 convertibles, while the regular Buick passenger palette lists 15 paint codes. Exact transmission sales codes and detailed component date codes remain open research.

**1968 Buick GS 400 convertible rear view; badges and wheels are supporting context rather than factory-identity proof**Greg Gjerdingen / Wikimedia Commons · CC BY 2.0

Price history

Values

Nominal dollars from original price sheets, auction archives, and approved value references.

Original Price

Base MSRP $3,528

44637 2-door hardtop coupe base price (1968)

1968 Buick Mid-Size Production
Base MSRP $3,672

44667 convertible base price (1968)

1968 Buick Mid-Size Production

Market Observations

Price guide value $18,600

Jul 28, 2026 · Hagerty Valuation Tools · Current guide point
July 2026 #3 good-condition benchmark for the exact 1968 Buick GS 400 two-door Sport Coupe with the 400cid/340hp four-barrel V8. · unknown · good Hagerty showed $18,600 for the exact Sport Coupe and 400/340 configuration in July 2026. This is an unadjusted guide value, not a completed transaction or individual-car authentication; the listed automatic-transmission adjustment is not applied.
1968 Buick GS 400 Sport Coupe valuation
Auction sale $25,000

May 21, 2025 · Bring a Trailer
GS 400 convertible 446678H315897 with a 400ci V8, four-speed manual, 2019 repaint, power front discs, Rallye wheels, and decoded 44667 body data. · modified · good Bring a Trailer records the $25,000 completed sale. The repaint, aftermarket steering wheel and audio equipment, electric-choke carburetor, four-speed, equipment, and lack of an original-to-car drivetrain claim keep this in the modified comparison path.
1968 Buick GS 400 convertible four-speed 446678H315897
Auction sale $22,550

Jun 10, 2012 · Leake Auctions
GS 400 convertible 446678Z115432 with the 400/340 V8, automatic transmission, air conditioning, power equipment, repaint, and aftermarket engine gauges. · modified · fair Hagerty records the $22,550 completed sale and identifies the same car's prior $20,350 transaction. The repaint quality, neglected engine compartment, trim wear, added gauges, automatic transmission, and convertible body materially affect comparison.
1968 Buick GS 400 convertible 446678Z115432 sale

Values move with paperwork, originality, options, condition, venue, and body style. High bids and guide values are labeled separately from completed sales.

Reference records

Options, Colors & Components

Source-backed details for trim, chassis, production, and authenticity.

Transmission

Factory transmission 3-speed manual
Factory transmission 4-speed manual
Factory transmission Super Turbine automatic
Factory transmission Three-speed floor-shift manual (standard)
Factory transmission Four-speed manual (optional)
Factory transmission Turbo Hydra-Matic 400 automatic (optional)

Options

Factory-rated 1968 Buick 400 V8Classic Muscle · Reference illustration

Positive Traction Positive Traction limited-slip differential optional · performance · Factory AMA axle section lists Positive Traction as limited-slip differential type/option.
Disc Brakes Front disc brakes optional · chassis · Disc brake equipment appears in the AMA brake and accessory/equipment listings for GS coverage.
Rallye Wheels Rallye wheels optional · appearance · Rallye wheels appear in the AMA accessory/equipment differential-weight listing.

Paint

**1968 Buick GS 400 convertible at a show; temporary event decoration is not factory equipment**SG2012 / Wikimedia Commons · CC BY 2.0

A Regal Black factory · solid
C Arctic White factory · solid
D Blue Mist factory · metallic
E Deep Blue Metallic factory · metallic
F Teal Blue Mist factory · metallic
G Ivory Gold Mist factory · metallic
K Aqua Mist factory · metallic
L Medium Teal Blue Mist factory · metallic
M Burnished Saddle factory · metallic
N Maroon Metallic factory · metallic
P Tarpon Green Mist factory · metallic
R Scarlet Red factory · solid
T Desert Beige factory · solid
V Charcoal Metallic factory · metallic
Y Cameo Cream factory · solid

Appearance

Rallye wheels optional · wheel
Chrome-plated wheels optional · wheel
GS 400 model identification factory · badge

Interior

Bucket seats optional · seat
Full console optional · console
Consolette optional · console
Tilt steering wheel optional · steering wheel

Chassis

Factory GS suspension specification set Suspension · factory
Power brakes Brakes · optional
Disc brakes Brakes · optional
Salisbury rear axle Rear axle · factory
Positive Traction limited-slip differential Rear axle · limited-slip · optional
GS 400 axle ratios listed in AMA table Rear axle · 3.23, 3.42, 3.64, 3.91 and 2.93 appear in the extracted axle-ratio table; exact standard/optional pairing requires table-image review · unknown

Production

GS 400 manual and Super Turbine transmission choicesClassic Muscle · Reference illustration

44637 2-door hardtop coupe by body · 10,743 · documented
44667 convertible by body · 2,454 · documented
1968 Skylark Gran Sport V-8 total · 13,197 · documented

Authenticity

Salisbury axle, Positive Traction, and documented ratio evidenceClassic Muscle · Reference illustration

**1968 Buick GS 400 hardtop with visible custom wheels and hood treatment**Sicnag / Wikimedia Commons · CC BY 2.0

GS 400 model/body-style evidence Factory AMA records use GS 400 and model/body references including 44637 and 44667 in the GS 400 pages. · Factory AMA model pages and vehicle/body identification records; verify against the vehicle serial/body data plates on an individual car. · fraud detection
Engine displacement claim 400 cu in Buick V-8 for GS 400 in the factory AMA engine table. · Factory AMA engine specification pages; confirm individual-car engine stamping/casting through service and parts references. · numbers matching
GS 400 engine production-code evidence Team Buick's 1968 engine-number table lists GS 400 engine number PR with 8 cylinders, 400 CID, 340 hp, 10.25 compression, 4BC carburetion, and MAN/AUTO transmission applicability. · Check the engine production-code stamping; Team Buick's Buick engine-identification page places the 1968-1972 400/430/455 production code between the two front plugs and the exhaust manifold on the left side. · numbers matching
Engine serial-number/VIN consistency Team Buick's Buick engine-identification page states that, for 1968-1972 400/430/455 engines, the engine serial number is just below the deck on the left driver's side and should match the VIN plate. · Inspect the engine serial-number stamping below the deck on the left driver's side and compare it with the vehicle VIN plate and supporting paperwork. · numbers matching
GS 400 trim-number evidence Team Buick's 1968 trim-number table lists GS 400 vinyl trim codes: Black 158/178, Blue 171, Green 170, Buckskin 173, and White 152/172. · Compare the body/data-plate trim number against the GS 400 trim-number table; use this as trim evidence, not as standalone proof of GS 400 identity. · fraud detection

Still Researching

authenticity markers New registry references resolve the GS 400 engine production code PR, 1968-1972 Buick 400/430/455 engine production-code and serial-number inspection locations, and GS 400 trim-number rows. Transmission-tag and axle-code decoding, plus car-specific paperwork/inspection, remain unresolved from target-specific factory decoding literature.
transmission A reviewed fact sheet supports standard or optional availability for the GS 400 three-speed manual, four-speed manual, and Turbo Hydra-Matic 400 automatic; exact factory sales codes and body-style constraints remain unresolved.

Codes & names