Hurricane Polymar

Both are episodic martial arts series that were made by the same creators  

Hurricane Polymar is mostly known as a Gatchaman clone as both have similar designs being a caped superhero with a helmet and both have abilities to create a windstorm. Although Hurricane had more power and abilities and he fought alone while Gatchaman mostly relies on tactics  

• Both series feature a goofy con artist mentor figure (Kuruma Joe and Arataka Reigen) • Both series feature a boy with a bowl haircut and an immense power which he keeps secret (Takeshi as Polymar and Mob as a psychic) • Both series feature a snarky comic relief non-human being (the dog and Ekubo)  

Extremely underrated anime. Old school anime and classic. They have the same feel, it's epic. This recommendation is hand chosen from me for you to represent what old school is. 

Both feature a similar level of action, violence, and even similar characters but Casshern is significantly more serious in tone.