I'd be inclined to say that its Univers Extra Condensed Italic, but Univers was released in 1957, and the car appears to be a 1954 to 1956 model...

Hi oldnick, Thank you for your reply!

Yes it seems Univers is a very close match, but alas... The model is a "1950 Oldsmobile Rocket 88 2 Door Hardtop" and the quotation marks on Univers differs from the typeface in the advert.

Headline Gothic seems a good match as well (though very late, 1995), but Univers is the winner so far.

Look at this link for instance, there appears to be minor differences throughout, so it cant be Univers...
http://www.flickr.com/photos/autohistorian/3971168200/

I wouldn't be surprised if it was hand-lettered. Film or process lettering is another possibility. I've checked specimen books for Photo-Lettering, Filmotype, and Lettering Inc. All of them had similar styles, but unfortunately none matches exactly.

(Coincidentally, the closest match from Filmotype, "Escort", is being digitized and will probably be released soon. I'm not the one working on it and not involved in release schedules, so I don't know exactly how soon.)

I wouldn't be surprised if it was hand-lettered

That's what I was going to say. It looks like something you'd find in the pages of Mortimer Leach's book Lettering for Advertising (1956).