See Figure 1
The Firebird was introduced in 1967 with a paired elliptical, single-leaf spring rear suspension. Shock absorbers were mounted on the spring brackets. Models with the more powerful optional engines were additionally equipped with radius rods to increase rear axle control. In 1968, the single-leaf rear springs were replaced with multi-leaf units and the shock absorbers were stagger-mounted, one on either side of the axle. A rear stabilizer also has been installed on the high-performance models such as the Formula and Trans Am.