An oil pan for an internal combustion engine includes a flange configured for attaching to the internal combustion engine, and a floor spaced apart from the flange by a first distance and configured for collecting an oil thereon. The oil pan further includes a wall interconnecting the flange and the floor and defining at least one passage therein, wherein the at least one passage extends from the flange towards the floor to a second distance that is less than the first distance. In addition, the oil pan includes at least one insert insertable into the at least one passage to a third distance that is less than the second distance to thereby define an oil drainback channel that is configured for draining the oil from the internal combustion engine to the floor.