Springs are what holds the vehicle up on the suspension, a longer spring (assuming similar stiffness) would result in a higher ride height. That's why basic leveling lifts are just spring spacers, used to add additional height to a stock spring.
The shocks have no effect on ride height, they are only there to control dampening & rebound, to help control how the spring moves up and down, but not height. They can however effect droop, which is how far the suspension extends out, which is limited to how far the shock extends, but not the ride height.