When Marcia and her partner are stopped by the police for the first time after the race has started, they are standing outside the car and Marcia's suit is zipped down. They watch the other cannonballers pass, and when she starts talking to the officer, her suit is zippped up so she can zip it down to retrieve her license.
Near the beginning the red Hawaiian Tropic stock car that Mel and Terry drive is a Chevy Chevelle/Malibu. After it's painted grey it's a Chevy Monte Carlo.
When the man on the motorbike races through the bar he has no helmet, then in the next shot he has a helmet on.
During the final race to the finish after the fight with the bikers, JJ and Victor pass the Rolls Royce twice, once just as Victor becomes Captain Chaos, and once just as they enter the city.
Throughout the entire film, the wheels on the Ambulance change from black wheels to having chromed hub caps and back again.
The Japanese team does not speak Japanese most of the time. They are mostly speaking Cantonese, a Chinese dialect. The only time that we hear Japanese language is when the Japanese TV show presenter is interviewing these two characters. It is also apparent during this scene that the Japanese TV presenter cannot understand what Jackie's character is saying when he addresses the audience in Cantonese, which is presumably part of the movie rather than an incredibly glaring oversight.
In the closing credits, Jackie Chan and Michael Hui are credited as "Mitsubishi Driver #1" and "Mitsubishi driver #2" respectively. They are driving a Subaru GL 4WD, not a Mitsubishi.
When Victor and JJ are in the ambulance being driven to hospital after the boat accident, they ask Hal Needham how far it is to get there. They are given the answer "About 10 miles". Then they ask how long it'll take to get there and are told "Oh about 4 or 5 minutes". That would be an AVERAGE speed of a minimum 120mph, something that'd be highly unlikely through city streets for a high-performance vehicle like a Lamborghini, let alone a souped-up ambulance.
In the road block scene, the unoccupied van's engine revs up as it accelerates towards the police car. In order for this to happen, someone would need to be pushing down on the gas pedal.
At the beginning of the race, the organizer explains to the racers that they will be punching a card at a time clock. When the first car pulls up, the passenger punches the card and the organizer looks at his watch and signals her to go. The punched card is the start time. It makes not sense for him to look at his watch.
Ramp visible (semi-hidden behind a beach umbrella and inflatable rafts) when Mel and Terry run their car into the pool.
Shakey Finch (who rides on the back of Bert Convy's motorcycle) is clearly replaced by a dummy in all wide shots. The most amusing of these is when they arrive at the blocked-off California road near the end of the movie; the dummy is lifelessly pitched forward on the motorcycle seat.
During the opening chase between the black Lamborghini and the police car, a shot is reused as the same RV can be seen driving around a corner on the freeway and towards the Lamborghini twice.
On the board behind Jimmy "The Greek" listing the odds for the Cannonball drivers, several auto makes/models are misspelled, including Merc "Zepher" [Zephyr], "Porche" [Porsche], and "Camero" [Camaro].
When JJ and Victor are riding in the ambulance after their boating accident, the medic's lips say "Like shit through a goose", but the audio track says "Like shot through a gun" when describing how the ambulance gets through traffic.
When Captain Chaos saves the Lamborghini Babes, we
hear a female voice say "You're so macho", but neither woman was speaking.
When Roger Moore's car is full of smoke, the "Bond Girl" makes a comment about wearing masks. Her mouth movement does not match.
All the shots of the Harley-Davidson motorcycle used by Brad in the Cannonball race are dubbed with sounds of high-revving four-cylinder engines instead of the typical 'potato' sound of a slower-revving Harley 45° V2.
Captain Chaos, during the fight with the bikers. He says his trademark "Dum, duh, duh, dum" with his mouth closed.
When J.J. lands the plane in the middle of a town square so Victor can get beer, if you look in the background, you can see the barriers that were used to block off the streets. You can also see people standing around watching in the background when Victor is running into the store for the beer.
During the "Big Roadblock" scene when the van explodes after hitting the patrol car, you can see the wire connecting the detonator to the explosives in the van. It flies across the far bridge piling.
Crewmembers and a camera are visible as the plane takes off after stopping for a beer.
In the scene where the airplane is taking off after JJ and Victor get their beer from the store, the airplane turns around in the street. From behind the aircraft, you can clearly see the camera crew at the end of the street filming the next shot as they are pulling up.
In the first scene between Fenderbaum and Jimmy "The Greek" Snyder sets a copy of the script on the counter between them.
When Blake and Fenderbaum deflate the tires of the Ambulance, the racers had not yet reached St. Louis, yet the flag of California can be seen flying in the background.
Even though the beginning of the race makes a blatant point of explaining that racers are scored by time, not order of arrival at the finish line, the ending seems to suggest the contrary. Since time is the main factor, any racer who started after the Lamborghini team should still have been able to check-in and beat them. Instead, everyone fights over being the first one to clock in, and the instant she checks in, everyone else simply gives up.
The team of Burt Reynolds and Dom DeLuise punched their time cards much later than the winning team of Adrienne Barbeau and Tara Buckman. Since they arrived at the finish line basically at the same time, Reynolds and DeLuise could've still easily won according to the rules set forth at the beginning of the race.
So somehow the rules changed in the middle of the race and it became the first team to punch their time card.
So somehow the rules changed in the middle of the race and it became the first team to punch their time card.
When Jackie Chan starts to watch "Behind The Green Door" on the car's VCR, the tape is visibly NOT inserted.
When the Rolls arrives at the hotel, Sheik strides to the rear of the car and a boom mic is visible in the windshield following the actor, the shadow of the mic then appears on the ground at the right-front tire.
Burt Reynolds and Dom DeLuise's characters are shown before the race that they know Sammy Davis Jr. and Dean Martin's characters yet for some reason Dom DeLuise's character seems oblivious that it is them when they offer to bless their vehicle.
Foyt says "niner" and "fiver" for numerals, but "niner" is the only standard deviation from the usual word so as to avoid confusion between the two words. In some countries, 5 is spoken as "fife" in radio communications to further emphasize the difference.
During the "Friends of Nature" event at the beginning of the film, George Furst's activist character is introduced as "Arthur J Foyt", a reference to auto racing legend Anthony J Foyt (A J Foyt). In the credits the character is named "Arthur F Foyt".