Z-filter media pack arrangements and methods for providing them are described. The preferred arrangements have a cured-in-place jacket around an outside of a coiled z-filter media combination. The preferred cured-in-place jacket is a mold-in-place overmold which includes, integral therein, a housing seal arrangement. Preferably a cured-in-place center core is used, most preferably one that has opposite concave ends with seal arrangements configured to seal a lead end portion of the coiled z-filter media combination.