Wow, Off On The Gear Ratio

My buddy said I had 4.10's in the rear of my Barracuda. I just got it up on stands today, and turned the pinion to check. It spun 5 revs for 1 rev of the tire, and its a big tire (275/60B14). I'm guessing 4.88's. Might just have to pull the center section and verify.