I'm prompted to make this post because of an email newsletter from Andrew Collins this morning in which he quotes the height of Khufu pyramid as 485'.
If John Neal's work is correct - and I'll let you know what I think when I've finished his book (I'm half way through) then in fact the intended height is 481 and one eleventh English feet.
This page gives a flavour of John's work:
If you're at all interested in metrology, then spend some time getting to grips with John's concept of a system of measuring units linked by specific, consistent fractions (176/175 and 441/440) with the English foot as the 'root' unit.
It is a bit of a mind-warp, but persistence pays off.
Edit: Here's a concise article by John that covers the main points of his thesis.