The perimeter of the Great Pyramid is 1000 yards. Exactly as designed.
In 1882, Flinders Petrie measured 1007.7 British Yards.
1000 yards is 1 second of equatorial rotation.
The ancients divided the day by 12 hours not 24.
Resulting in 43,200 seconds in a day.
43,200s x 1000y = 43,200,000 yard circumference.
To convert to British yards multiply by 1.0077.