To expand on FumbleFingers' comment:
I don't think there is any official rule, but to me, "over the past..." has always implied a continuous process, while "in the past..." implies discrete (separate) events. So one would say "I learned to drive over the past three years," but "I took my drivers' test sometime in the past year."
Where it gets a bit tricky is that multiple discrete events can be described as one continuous trend - so you could say either "I had met him several times in the past year," or "I had met him several times over the past year." What sounds better in these cases is, as far as I can tell, quite random, so I unfortunately can't give a rule, but either is correct.
For the example you gave, you described a process (the process of learned about supercars), so I would use "over" in this case.
I must first correct another part of your sentence: you wrote were are at this side – I think you meant either
Only a few of his friends were at his side.
or
Only a few of his friends are at his side.
In this structure of this sentence, few is an indefinite pronoun referring to friends, and since friends is plural, you use were and not was.
Best Answer
If on the page of N-Gram you link to, you click through "a few does", you will see in most examples the "does" in question is not the third person singular of the verb "to do", but the plural of the noun "doe" -- a female deer. Example:
"A few" is plural, and takes "do".
Addendum: Oh, hey, google's N-Gram doesn't respect punctuation, and there's quite a lot of "a few does" hits which have punctuation between "few" and "does" which completely changes the relationship of the words. Examples:
Apparently google's N-Gram viewer isn't necessarily so good for phrases.