A gasket well/gasket combination (30) is provided, and may be particularly useful for use in a header/tank assembly (12) for a heat exchanger (10). The combination (30) includes a gasket well (32) defined by a base wall (36) and a side wall (38) extending upwardly from the base wall (36), with the side wall (38) including an upwardly opening slot (40) having a width (SW). The combination further includes an elastomeric gasket (34) shaped to be received in the gasket well (32) and compressed between the base wall (36) and a mating part to form a sealed connection. The gasket (34) includes a seal bead (50) and a locating feature (52) having a tab (62) extending outwardly from the seal bead (50) to a terminal end (64) of the tab (62), with the tab (62) having a transverse width that does not increase from the seal bead (50) to the terminal end (64). The transverse width is larger than the slot width (SW) with the tab (62) in an undeformed state. The gasket (34) is receivable in the gasket well (32) with the tab (62) pinched in the slot (40) across the transverse width to retain the gasket (34) in the gasket well (32).