However, here's what we can find:
* Q-taro: Most sources credit the voice to Ichirō Nagai. He was a very prominent voice actor in the 60s and 70s, known for roles like "Astro Boy" and "Kimba the White Lion".
* Other characters: It's difficult to confirm the rest of the cast without access to detailed Japanese-language sources or old Japanese anime guides. It's likely many of the other voices belonged to popular voice actors of the time.
Where to find more information:
* Japanese language websites: If you can read Japanese, searching online forums or Japanese anime wikis might yield better results.
* Old Japanese anime guides: These may have cast lists from the 1960s, but they can be hard to find.
I hope this helps you get started on your quest for the "Obake no Q-taro" voice cast!