A front upper frame connection casting can comprise a vertical front upper frame connection boss oriented in a first downward direction and configured to weldably attach to a first elongate support member; a rearward angular front upper frame connection boss oriented in a second downward direction and configured to weldably attach to a second elongate support member different from the first elongate support member; and a center cast section castably attached to the vertical front upper frame connection boss and the rearward angular front upper frame connection boss. The center cast section can have a top surface configured to weldably attach to a front upper body support and frame connection fabrication of a space frame of a rear haul truck.