The full-size Mercurys were redesigned for 1965 with a new torque-box frame and a more slab-sided look, reflecting the popularity of the Continental. The Breezeway window was now only available on pillared sedans, with all two door hardtops being fastbacks. Not all two door hardtops were of the “fastback” style. Ford had made an early 1966 model with a “notchback” design, which was discontinued part way through the model year.
The Mercury-exclusive 410 cu in (6.7 L) and the 428 cu in (7.0 L) FE engines were added for 1966. The 1966 model two door Mercury Monterey hardtop, was built in two half-year variants. The first half of the 1966 year was built with a “Notch-back” rear window version,(which looked more like the four door version) while the second half of the 1966 model year was redesigned with the “fast-back” rear window. 1967 brought a refresh, and the vertical Breezeway roofline disappeared although they could still be had with a drop-down rear window. The 410 was dropped for 1968.