At the end of the Daytona race both drivers swerve around crashed 50s cars. But the main race shots were filmed in the mid 60s with no older cars in any footage. Then Fabians car which was a mid 60s blue and white Plymouth becomes an early 60s car in monotone blue as he crashes over the guardrail.
In shots of both Frankie Avalon and Fabian leaving the pit stop they show a shot of the drivers feet working the clutch pedal. The pedals go down thru the floor. Mid 60's cars pedals went up under the dash.
When the 99 car goes over the guardrail at Daytona, two fireball explosions happen underneath the car shooting flames up into the air, one on the track side of the guardrail and one on the far side behind the guardrail. Neither explosion had any reason for being other than visual additions to the crash.