Exemplary modular gas blocks may include a body having inlet and outlet ends. The body may define a portion of a first gas path along a length of the body and may define a second gas path along a width of the body. The first gas path may include channel segments defined within the body. The inlet end may define a gas inlet that is coupled with the first gas path. The body may define first fluid ports that are coupled with the first gas path. A fluid port of the first fluid ports may be coupled with the gas inlet. The first fluid ports may be coupled with one another via a respective channel segment. An upper surface may define a lateral fluid port that is spaced apart from a first fluid port along the width and is coupled with the first fluid port via the second gas path.