TACTICAL TWIST

WITH GM’S 400- cubic-inch limit for mid-size cars rescinded for 1970, Buick, Olds, and Pontiac responded with 455s and Chevrolet with a 454. A 350-hp 455 for the GS 455 and GSX, and an optional 360-hp Stage 1 escaped from Flint, and Lansing released a 365-hp 455 for the 4-4-2 and an extra-cost 370-hp W-30 version.

Buick and Olds replaced their 400 engines, but Pontiac retained its 350-hp 400 for the GTO and made its new 360-hp 455 a mid-level option for it and The Judge, with the extra-cost 366-hp Ram Air III 400 (standard in The Judge) and the round-port 370-hp Ram Air IV 400 remaining the top performers.

These three 455s were each division’s own design, and since they retained the same outer dimensions as the 400s they replaced, there was still