Overload looks like a mixture between G1 Ultra Magnus and Ironhide (the former being his original name in Japan).  His chest and head in robot mode are formed by the Minicon Rollout, making him something of a Headmaster or Breastmaster. Rollout can become one, but then Overload would be headless. There is one nice gimmick, though: When pushing Rollout into Overload's chest you get the classic Transformation sound as a sound effect.