A valved conduit, comprising: a subassembly of: a conduit graft comprising a longitudinal tubular portion between an upper end and a lower end, the lower end having a collar portion; and an annular sewing ring comprising an inner core and an outer fabric covering, the sewing ring being positioned adjacent the lower end of the conduit graft whereby the collar portion contacts and is secured to an inner wall of the annular sewing ring; wherein the subassembly of the conduit graft and sewing ring is independently leak tested, a prosthetic heart valve having an inner support frame covered with fabric and defining a flow orifice and a plurality of leaflets extending inward from the support frame to ensure one-way blood flow through the heart valve, wherein the heart valve is positioned within the lower end of the conduit graft and the fabric covering the support frame extends downward in a tubular segment and is folded radially outward underneath the subassembly of the conduit graft and sewing ring and secured thereto with sutures; a holder attached to the heart valve and extending from the heart valve out of the upper end of the conduit graft. a subassembly of: a conduit graft comprising a longitudinal tubular portion between an upper end and a lower end, the lower end having a collar portion; and an annular sewing ring comprising an inner core and an outer fabric covering, the sewing ring being positioned adjacent the lower end of the conduit graft whereby the collar portion contacts and is secured to an inner wall of the annular sewing ring; wherein the subassembly of the conduit graft and sewing ring is independently leak tested, a prosthetic heart valve having an inner support frame covered with fabric and defining a flow orifice and a plurality of leaflets extending inward from the support frame to ensure one-way blood flow through the heart valve, wherein the heart valve is positioned within the lower end of the conduit graft and the fabric covering the support frame extends downward in a tubular segment and is folded radially outward underneath the subassembly of the conduit graft and sewing ring and secured thereto with sutures; a holder attached to the heart valve and extending from the heart valve out of the upper end of the conduit graft. a conduit graft comprising a longitudinal tubular portion between an upper end and a lower end, the lower end having a collar portion; and an annular sewing ring comprising an inner core and an outer fabric covering, the sewing ring being positioned adjacent the lower end of the conduit graft whereby the collar portion contacts and is secured to an inner wall of the annular sewing ring; wherein the subassembly of the conduit graft and sewing ring is independently leak tested, a prosthetic heart valve having an inner support frame covered with fabric and defining a flow orifice and a plurality of leaflets extending inward from the support frame to ensure one-way blood flow through the heart valve, wherein the heart valve is positioned within the lower end of the conduit graft and the fabric covering the support frame extends downward in a tubular segment and is folded radially outward underneath the subassembly of the conduit graft and sewing ring and secured thereto with sutures; a holder attached to the heart valve and extending from the heart valve out of the upper end of the conduit graft.