Continuity mistake: When Waldman is telling his wife Alice how disgusting her dog is, the way he holds his spoon keeps changing between cuts.
Continuity mistake: When Sam Caine and the intruder fight over a shotgun and they both fall over, the shotgun disappears. A sound effect of the gun shooting is even inserted to cover up the fact that it just vanishes.
Answer: A 1966 Ford Galaxie-500 XL. There's a website that lists the vehicles used in the movie.