The Pontiac Firebird Formula was the "little brother" to the Trans Am. It was introduced for the 1970 model year and continued through the 1981 model year. It was reintroduced in 1987 and continued through the 2002 model year.

1970 to 1974 Firebird Formulas

The 1970 to 1974 Formulas are identified by an aggressive twin-nostril hood and Formula emblems on both front fenders. The Firebird Formula could be ordered with the same engine options as the Trans Am, except in 1970, when the Firebird Formula could come with the Trans Am's Ram Air III engine, but not the top-of-the-line Ram Air IV engine. In 1973 and 1974 you could even order the 455-SD high-performance engine.

1975 to 1981 Firebird Formula

In 1975 to 1976, the Firebird Formula no longer had the option of the Trans Am's 455 engine, but in 1977 to 1981 it could have any Trans Am engine. A styling-revision in 1975 meant the Firebird Formula's twin-nostril hood was less aggressive than previous years, and this basic style carried through the 1981 model year.

1988-1992 Firebird Formula

The Firebird Formula was brought back by popular demand and was available with a Chevrolet 305 or higher-horsepower Chevrolet 350 engine. The car is identified by large Formula decals on both lower doors.

1993 to 1997 Firebird Formula

In 1993, the Firebird Formula was completely revised and featured a high-horsepower Chevrolet 350 ci LT1 engine, the same engine that came in the Trans Am. The 1993 to 1997 Firebird Formulas have a "Formula" emblem in a raised, body-colored script found on the lower portion of both doors. The Firebird Formula came with a cloth interior, unlike the leather interior that came on the Trans Am. The bodystyle continued through 1997.

1998 to 2002 Firebird Formulas

In 1998, the Firebird Formula received a minor styling revision with a new front end, hood and taillights. A new engine came standard, a Chevrolet 346 ci LS1, the same engine that came on the Trans Am. The Firebird Formula continued through the end of the 2002 model year. Like 1993 to 1997, these Firebird Formulas have a "Formula" emblem in a raised, body-colored script found on the lower portion of both doors and came with a cloth interior, unlike the leather interior that came on the Trans Am.

Source:

TheFormulaSource.com

LS1Tech.com: Pontiac Firebird

TransAmWorld.com: Firebird History

More Information:

Firebird Nation