Pretty sure he was 6'5-6'6 in his prime.Hogan was 6'3" at his peak. This site claims he's now 6'3" but I'm not sure if he's even that tall at this point.
Andre was at most 5 inches taller, and Andre was definately not 6'8, but probably around 6'10.
At age 50, and after multiple surgeries, Hogan was still as tall, maybe a smidge taller, than The Rock.
And Rock's official NFL height was 6'4, and I'm guessing they use accurate heights.