How much is a Buick Skylark GS worth in 2026?

The Buick Skylark GS is one of the cleanest-looking muscle cars of the 1960s and 1970s — and one of the most underpriced. I've inspected hundreds of supposedly high-performance A-body cars over the years, and the GS 455 Stage 1 still surprises people who haven't driven one. It does not feel like a big car. The torque is immediate and sustained in a way that high-revving small-blocks cannot match.

GS Lineup Overview

• GS 340 / GS 350 (1967–1972): Small-block entry, excellent driver, $20,000–$38,000
• GS 400 (1967–1969, 400 ci big-block): $28,000–$55,000
• GS 455 (1970–1972, 455 ci): $32,000–$60,000
• GS 455 Stage 1 (1970–1972): $42,000–$85,000 for documented Stage 1 cars

The Stage 1 Package

The Stage 1 option (RPO W30 for Buick) specified a 455 cubic-inch big-block with a performance carburetor, higher-lift cam, cold-air induction, and revised valvetrain. Factory rating: 360 hp / 510 lb-ft. The broadest torque curve of any production muscle car engine — the Stage 1 makes peak torque at 2,800 rpm and holds it to 4,400 rpm, giving it a drivability advantage at street speeds that high-revving small-blocks cannot match. The market premium for a real Stage 1 is real, but documentation is critical. Verify the W30 RPO code on the cowl tag and broadcast sheet — it should appear there on a genuine factory Stage 1.

Why It's Undervalued

Head-to-head, a documented GS 455 Stage 1 out-torques a Chevelle SS 454 LS6. It outperforms the Pontiac GTO Judge in period road tests. Yet the market prices it 20–35% below both. The Buick nameplate works against it. Buyers who did their homework have been accumulating GS 455 Stage 1 cars for years, and the supply of clean, documented originals is thinning rapidly.