1970 Buick GS455 Concours Restoration Guide

The 1970 Buick GS 455 is the apex of the Gran Sport story. The 400 ci engine was replaced by the all-new 455 ci V-8 — the largest displacement of any 1970 intermediate-car engine from any American manufacturer. The standard 455 was rated at 350 hp; the Stage 1 version carried a conservative 360 hp rating with documented performance that exceeded the manufacturer's claims. Buick also introduced the GSX package — a visual and performance statement that added a specific paint treatment (Saturn Yellow or Apollo White with black stripes), rear spoiler, and side stripes — making the GSX one of the most striking muscle cars of 1970.