The Race Against the Mammoth Car (Part 2)
Satisfied that the Mach 5 is forever submerged in Lake Icy Chill, the Mammoth Car drivers resume the race. Through his telescanner, Speed sees them leave as he reaches soil. Trixie sends a message in the homing robot to Inspector Detector. The stolen gold is aboard the Mammoth Car. From his plane, Cruncher Block sees the Mach 5 on the road. At the refueling station, Speed and Trixie are fired at. Escaping into a mining tunnel, they jump on top of a speeding trolley car, which crashes. Meanwhile, at the refueling station, Spritle and Chim Chim sneak out of Cruncher's plane. They, too, escape into the tunnel, which turns out to be Cruncher's headquarters. There, Speed and Trixie are tied to a trolley loaded with three tons of dynamite. Ultimately, Racer X arrives and saves them. At the next checkpoint, the Inspector searches the Mammoth Car. Again, he finds nothing. Speed reaches the checkpoint; Spritle and Chim Chim slip out to hide in the Mammoth Car.
Aired 14/10/1967EP 8 - The Race Against the Mammoth Car (Part 2)

Speed Racer
The Mach 5 is one of the fastest and most technologically advanced race cars built by man. Equipped with various gadgets and a powerful engine, it provides a challenge for anyone who would dare race against it. The driver of this amazing vehicle is Gou Mifune, a teenager who dreams of breaking into the world of professional racing.
In spite of this, Gou's father and the creator of the Mach 5, Daisuke Mifune, does not want his son anywhere near a racetrack. Undeterred, his girlfriend Michi, younger brother Kurio, and Kurio's monkey sidekick Sanpei become Gou's biggest fans as he sets out to become the greatest racer of all time.
However, Gou soon learns that becoming a professional racer is not easy. From the underhanded plots of corrupt businessmen to stiff competition in the form of his rival, Racer X, Gou faces many obstacles on the road ahead, and has a lot to prove before he can cross the finish line.
(Source: MAL Rewrite)