Trucks are not level. The bed sits higher than the cab making the truck look as though it is leaning forward. Leveling the truck requires adding body spacers to the front frame or removing a leaf from the rear suspension. The action is done for purely aesthetic reasons, but there are some downsides to leveling a truck, no matter if the truck is a Chevrolet or some other model truck.
The truck's bed is elevated due to the suspension on the rear, which is composed of several leafs. The leafs and other suspension parts allow the truck to carry a certain load in the bed of the truck, which is where the truck gets the qualifier of half-ton or quarter-ton pickup. The half-ton can carry a load that weighs up to 1/2 ton in the bed. The quarter-ton pickup can carry a load that weighs a 1/4 ton without damaging the suspension or losing power. Removing a leaf to level the bed drastically reduces the truck's load capacity. Attempting to put a 1/2-ton load into a pickup with a leaf removed can cause the tires to rub the wheel wells, the shocks or struts on the rear to be overly worked, or the rear axle to be placed under heavy strain.
An alternative to removing a leaf is adding spacers to the frame where the cab meets the frame, which is called a body lift. The act levels the truck but puts the driver in a precarious situation when carrying a load. The truck remains capable of carrying a 1/2-ton or 1/4-ton load, but the load weighs down the bed. The spacers force the cab to angle upward at that point, limiting the field of view of the driver. The angle of the cab, at that point, can also place stress on the drive shaft due to the connection of the shaft and the cab.
A suspension lift can add spacers to the front suspension or raise the torsion bar a few inches. The downside to a suspension lift is the impact on the ride. Normal suspensions are geared for a specific weight and angle. The suspension lifts alter the center of gravity, causing a harsher ride while going down the road. The impact to the quality of the ride also impacts the actual suspension, causing damage to struts, sway bars, and other aspects of the suspension and steering systems. The process is a cheap way to go but has more potential for damage.
