At the end when the cars reach their destination, Seymour arrives with the majority of the others in his Aston Martin. Later when the three other cars arrive, one of those is his Aston Martin. At this point he has already gotten out of his car.
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.
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.
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.
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.
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.
When Terry and Mel are retuning the Hawaiian Tropic car, Terry tells Mell to "hit it one more time". We then hear the sound of the car trying to start even though one of Mel's arms is on the window and the other on the steering wheel.
At random times during the race, Seymour has his black gloves on and off. At one point where he is not wearing them while driving, his female passenger goes to press a button. He stops her, grabbing her hand, clearly wearing a black glove, yet back to the front-on shot he is clearly not wearing the gloves.
When the Cannonballers are standing around listening to the Instructions, the camera pans through the crowd. J.J. and Victor are standing nowhere near Marcie and Jill. The camera cuts to the speaker, then pans the crowd again. In a close up, J.J. and Victor are right next to Marcie and Jill.
When Foyt accidentally puts the unoccupied van into a collision course with the police car, the driver side door is open in one camera shot and inexplicably closed in the next. Also, the van is moving in a different direction.
When the ambulance stops for gas in Missouri, J.J. is still fuming about the all the time lost due to Jimmy Blake and Fenderbaum letting down the ambulance tyres. Yet somehow Blake and Fenderbaum are now behind them, arriving at the gas station after the ambulance.
The closing celebratory scene shows Burt Reynolds spitting champagne twice while Farrah Fawcett covers her head from spraying bottles. This scene is immediately repeated again from a camera boom panning out from a different angle.
When the ambulance stops to get gas at 7-11, they are supposed to be in Missouri, however the gas pumps have Georgia inspection stickers. Additionally, the red & white Ford van and the blue Ford station wagon also have Georgia license plates.
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.
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.
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.
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.
When the Lamborghini babes are talking to Jamie Blake he says, "The cops would never give that a second glance", to which Jill replies, "220 miles per hour, they aren't gonna get a second glance". The Lamborghini Countach the girls are driving is an LP400S US specific model which has a top speed of 182 mph.
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.
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.