When Branco and Drake pull up to the hunting cabin, it is still daytime outside. When they enter it, it is now nighttime.
On the boat dock in Los Angeles, Zoltan's coffin, with the dog still sleeping inside it, is opened in the daytime. Zoltan's body should have instantly disintegrated into dust the instant that happened.
Michael Drake looks at a daguerreotype of Count Igor Dracula, his ancestor, and Zoltan, which some vampire legends suggest is impossible, because vampires' images supposedly cannot be captured on film. However, it is never specified that this aspect of vampire mythology is followed by the film.
One of the Jeeps at the excavation site in the film has the remnants of lettering that says "U.S. Navy" on it.
Veidt Smit is seen driving a hearse (which still had its keys in the ignition and which he stole from a funeral parlor off-screen) in order to transport Zoltan in his coffin while following the Drakes to the forest. Smit became a "fractional lamia" (an undead creature who is only part vampire and which was specifically created for this film) in 1670, less than 300 years before the year the main story in the film takes place (1977), and therefore could not and should not have even known how to drive a car, much less learned how to drive one that quickly.
The film contains a flashback to Transylvania, Romania in 1670, depicting Zoltan - an innkeeper's dog - being bitten and fed upon by Count Igor Dracula (in bat form) as a replacement for a kill that was stopped by the dog's barking out an alarm. However, Zoltan is a Doberman Pinscher, a dog breed that did not yet exist at that time, first being bred more than 200 years later in Germany about 1880.
The Dracula tomb site, which is supposed to be in Romania, is covered with eucalyptus trees.
Inspector Vaclav Branco refers to Michael Drake as the last surviving mortal member of the Dracula family, but he also meets Drake's wife named Marla and his two children named Linda and Steve. It is possible, however, that Branco is referring to Drake being the Dracula family's last direct adult male descendant, since Veidt Smit and Zoltan appear to have little to no interest in having either a woman or a child as their master.