When Carol and John are walking through the junkyard they go past many 1963, 1962, 1961, and 1960 cars. It would be improbable for these "late model" cars to already be in a junkyard in 1963. There is a 1963 Studebaker Lark, a 1961 Pontiac, and a 1960 Ford for instance.
Curt watches The Adventures of Ozzie & Harriet on televisions in a store window, sometime close to midnight. Sitcom reruns were not late-night staples in 1962, and "Ozzie & Harriet" was never scheduled later than 9:00 PM in prime time.
While it was plausible for the double yellow road striping to be seen on USA roads in 1962, during a car chase scene there is a road with what seems to have yellow dashed striping in place along with white center lines. Yellow dashed center lines were introduced from the beginning of 1972, and therefore the researchers to the film must have accidentally overlooked a section of road that had just been re striped.
Wolfman Jack's radio broadcasts throughout the film are ostensibly airing on Mexcian station XERB, as identified by various jingles. However, in 1962 (when the film is set) he was broadcasting for another station, XERF; he would not move to XERB until 1965.
Near the end of the movie, Steve throws Toad and Debbie out of his '58 Chevy at Mel's Drive-In. As Toad and Debbie are stepping out of the car, there is a reflection of a boom mic moving along the left rear portion of the car's roof.
Though Debralee Scott is listed as "Falfa's Girl" in the credits, she is only riding with him in earlier scenes. She is mysteriously gone later and replaced by an uncredited blonde actress. Later the blonde also disappears without explanation and Falfa "picks up" Cindy Williams character.
When Carol runs from the Studebaker to Milner's coupe, she reaches through his passenger window to open the door with the inside latch handle, without trying the exterior handle (which isn't working, as Toad does the same thing); however, Carol would not yet have known that.
While listening to Wolfman Jack at Mel's, Curt hears the Wolfman say that he'll be going off the air in five minutes at midnight. Curt goes to the studio to make a request, but the clock in the background shows that it's only 7:25 pm.
Falfa and Milner prepare for the street race (their first meeting). Falfa has a blonde sitting next to him in the '55 Chevy. When the light turns green, they take off. During the next few cuts of the two cars racing down the street, there is no passenger visible in Falfa's car. When the next light turns red, Falfa guns his car to go through the red light, and the blonde passenger has reappeared.
After Falfa rolls his Chevy, Milner aids him up the slope to the roadside. Falfa clearly has his white cowboy hat in his hand. Edit scene to the Chevy explosion. Scene cuts back to Milner handing Falfa his white cowboy hat.
When Milner gets blasted with the shaving cream, he wipes it away with his hand - all but a small smudge between his eyes. Even though he missed this smudge, it's clearly gone the next time we see his face.
When John Milner is cruising the strip for the first time he is supposedly alone in his rod, however right after the guy in the black coupe tells John to watch out for the cops, you can see that there's someone in the passenger seat beside him.
Falfa and Milner race on Paradise just before sunrise. Paradise Road runs west out of Modesto, but the sun was rising over the mountains, which are clearly visible in the near distance. That shot was likely taken from the ocean side of the Pacific Coast Range near Petaluma, somewhere off of Lakeville Highway.
In the final scene Curt walks toward the airplane's open door to board while the number one engine (left outboard) is starting up. In real life, a pilot would never start an engine on the boarding side with a door still open and passengers behind a running engine.
The Beach Boys song "All Summer Long" - which plays over the end credits - was released in the Summer of 1964 although the movie is set in the Summer of 1962, some two years before the song's release. But the characters do not hear it, only we do; and it is a suitable way of moving into the post-1962 "future".
Carol's parents won't let her listen to Wolfman Jack partly because he is a "negro." Wolfman Jack in fact is not African American, but because Rythmn and Blues and rock have African American roots, her parents during that era, probably figured that Wolfman was African American.
When the Wolfman announces Curt's dedication request on the air, he tells the blonde to meet Curt at Burger City - but Curt was waiting at Mel's Drive-In. But if you check the Mel's Drive-In sign at the beginning of the film, you'll see "Burger City" at the very bottom of the sign.
Not only is Milner's yellow hot rod missing an antenna, it doesn't even have a car radio. It never did and still doesn't have one, the car being now owned in original condition by Rick Figari from San Francisco.
At the radio station, the control board is a Gates Stereo Yard, the station is AM while a "yard" would only be used at an FM Stereo station. None of the meters moved. None of the lights on the cart machines ever changed.