ALTHUDCF is an optional text lump that can change the appearence of ZDoom's Alternative HUD (added in version 2.2.0).
The following will change the ammo counter icons in the lower right to show the large boxes instead of their smaller variants.
Clip AMMOA0 Shell SBOXA0 RocketAmmo BROKA0 Cell CELPA0
This one will remove the ammo counters altogether.
Clip "" Shell "" RocketAmmo "" Cell ""