The second-generation debut for the 1970 model year was delayed until February 26, 1970, because of tooling and engineering problems; thus, its popular designation as a 1970½ model, while leftover 1969s were listed in early Pontiac literature without a model-year identification.This generation of Firebirds were available in coupe form only; after the 1969 model year, convertibles were not available until 1989. Replacing the "Coke bottle" styling was a more "swoopy" body style, while still retaining some traditional elements. The top of the rear window line went almost straight down to the lip of the trunk lid. The new design was initially characterized by a large C-pillar, until 1975 when the rear window was enlarged. Originally, the "wraparound" style window that occupied more of the c-pillar was initially supposed to be the design, but problems with the glue and sealing of the rear window led to the flat style window being used until the re-designed body in 1975. This style became the look that was to epitomize the F-body styling for the longest period during the Firebird's lifetime.