Distal connector assemblies that are on the distal end of medical lead extensions provide increased rigidity by including a rigid holder that contains the electrical connectors. The electrical connectors are separated within the rigid holder by insulative spacers that may be individual items or may be formed from a compliant carrier that the electrical connectors may reside within where the carrier is positioned within the rigid holder. The rigid holder may also contain a set screw block defining set screw bore or the rigid holder may include an integral portion that defines a set screw bore. The integral portion may include a slot to allow a molding pin loaded with the electrical connectors and other components to be dropped into a cavity of the rigid holder. An overmold may be present to surround the rigid body containing the electrical connectors and insulative spacers.