Snubbers only work if your leaf springs are soft enough to allow the axle to wrap under accelleration. Once the wrapping motion begins, the snubber contacts the undercarriage, stopping wheel travel, then leveraging the torque against the weight of the body to plant the tires. Additional leaves added to the spring pack, clamping the front section of the spring pack, or switching to super stock springs changes the situation enough that snubbers may become ineffective. The three above additions can change spring wrap to spring lift, which creates body seperation which will move the snubber away from the floor, negating its ability to do its job as the springs are now working as intended.
If your snubber is banging the floor during normal driving, then you may want to adjust it back until it stops hitting on all but the most severe bumps or launches. If you go to the track where traction is abundant and the surface is smooth, then adjust it back up to within an inch.