Answer:
The answer to your question would be that the element necessary to complete the sentence above is the predicate.
Explanation:
The sentence above is a sentence fragment. In order to be a sentence, a group of words needs to have at least one independent clause. An independent clause is any group of words that contains both a subject and a verb and can stand on its own. In this case, the sentence does contain a subject (My father's 1969 Volkswagen beetle) but it lacks the predicate.
