Already standard in the Cobra GT 3.0, but a nice optional for earlier Cobra GT’s . The lighter 2-speed gearbox of the Viper 977, which need the new version alu center blocks to be mounted.
To use the new 2-speed gearbox also the new type pinions on the clutchbell are needed # 903646
600706 2-speed center blocks SL8 XLI 811GT
600716 2-speed set SL8 XLI 811GT
Source : Serpent