i bought a 1990 RRC that has a leaking head gasket. well let me back up. the RRC i bought came with a bypassed heater core and a new genuine core in the box from RN. im not actually sure what the problem with the core is. did it only leak because of the blown head gasket, or did it leak and let the coolant level down too low and that caused the head to blow? etc. etc. I have the instructions printed off from AB or RN, i forget who, but I found it amusing that the first step is to remove both front doors for easier access. Im pulling the heads currently to replace the head gaskets and I figured I will deal with the core once its actually drivable and registered.