The present disclosure relates to a flake graphite cast iron simultaneously having high strength, good machinability, and fluidity, to a method for manufacturing same, and to an engine body comprising the flake graphite cast iron for an internal combustion engine and, more particularly, to a method for manufacturing a flake graphite cast iron, for an engine cylinder block and head having improved castability, a low possibility of the occurrence of chill due to ferroalloy, stable tensile strength and yield strength, and good machinability by adding a trace of strontium in a cast iron including carbon (C), silicon (Si), manganese (Mn), sulfur (S), and phosphorus (P), which are five elements of the cast iron, molybdenum (Mo), a high strengthening additive, and copper (Cu) while controlling the ratio (S/Sr) of the sulfur (S) content to the strontium (Sr) content in the cast ion.