[Excaliber]

I think 2700 (or more) would be in the ball park. Some MAKES like FFR are almost always lighter, but equally most of those are small blocks (often near stock).

Original 427's? Hmmmm,,,,, 2200-2300?

Could be more than the just the weight here, you don't suppose someone "fudged" the 1/4 mile numbers back in the day? Perhaps it was close to 12.5 or higher? Pretty common to fudge either the car or the numbers "back in the day".