In his 2019 autobiography "Idol Truth" Leif Garrett revealed he proposed marriage to his longtime girlfriend Nicolette Sheridan while making this film in New Zealand. She accepted, but later changed her mind.
Cliff Robertson, who was nearly 61, was considered too old to play a racing driver in this film.
The American DVD release used an image of Leif Garrett from when he was about 17 or 18, several years before this film was made.
The astute will note that when Casey is changing plugs beside the call box at Queenstown the Trans Am has the distributor at the rear of the intake manifold. This is a Chevrolet "small-block" V8, probably a 350 (most ubiquitous performance V8 in the world at the time), not a Pontiac engine.