The Hills Have Eyes [1977]

When their camper breaks down in the desert on their way to California, a desperate family struggles to survive the attacks of a bizarre cannibalistic family, hungry for fresh meat and determined to terrorize the innocent vacationers. As members of the Carter clan fall prey to these inbred marauders, only a son and daughter remain to rescue their kidnapped infant and seek vengeance against the savages who have destroyed their family.