The original version of “National Lampoon’s Vacation” looked very different from the one we know and love today. In the book “Wild and Crazy Guys: How the Comedy Mavericks of the ’80s Changed Hollywood Forever” author Nick de Semlyen explains what happened with the original cut. The author writes:
“Also cut: the entire original ending, in which Clark arrives at the amusement park (no longer Disneyland, but the fictional Walley World) to find it is temporarily closed, causing him to fly into a rage and take the park’s creator hostage in his own home.”
In the DVD commentary of the film, director Harold Ramis explained further. “We had to re-think the whole end of the movie,” the director said. Writer John Hughes came up with a new ending to the film where Clark forces a security guard (John Candy) to open the park. The new scenes were shot over the span of three days at Six Flags Magic Mountain in Valencia, California. And the new ending literally made Chevy Chase sick.
Much of the new footage involved the Griswolds on a roller coaster. “The reshoot was less fortuitous for Chase, who became nauseated after having to ride a roller coaster over and over again,” Semlyen wrote.
While the re-shoots left Chevy Chase nauseous, they might have also saved the movie.