All Avalanche models come with a standard 320-hp 5.3-liter V8 FlexFuel engine with Active Fuel Management coupled to a six-speed automatic transmission. All trims are now equipped with roof rails, Bluetooth, and rear audio controls.. Safety features that come standard on all models include front seat and side curtain airbags; LATCH rear-seat child safety seat anchors, Stabilitrak with Proactive Roll Avoidance and the OnStar crash-notification system Bluetooth