I'm looking for a kids' fantasy movie end of 70s beginning of 80s where my memory recalls those few images: 2 or 3 kids traveling in a boat, their journey beginning in a sewer hole. Then they face a dragon with seven heads. Any idea of the title guys?

Actually, I found it. It was a Hungarian movie produced in 1971. The original name was Hahó, Öcsi! The English version was named Hi, Junior and it also had another name: Tony and the Tick-Tock Dragon.

It's available in DVD in Hungary but only in Hungarian. If anyone has the US version available to buy / download, let me know.

Cheers.