An implantable electrical connector system, which may be used as part of an electrical lead, a connector block on an implantable pulse generator, or the connector of a lead extension. The distal most electrical contact on the proximal end of the lead (or lead extension) is adapted to provide registration or alignment of all of the electrical contacts of the proximal end of the lead (or lead extension) with electrical contacts of the distal connector of a lead extension or the electrical contacts of a connector block of an implantable pulse generator (IPG). In an exemplary embodiment, the distal most electrical contact on the proximal end portion of the lead may have a flange or shoulder that is adapted to engage the distal electrical contact of the female connection section of a lead extension or connector block. Most preferably, in this exemplary embodiment, the flange or shoulder is an integral part of the distal most electrical contact.