Monitor Lizard Enclosure?

I thinking of getting a nile monitor but websites say they grow to ten feet and some say 4 feet and i realy like them ive been doing reaserch and every website has a differnt size and my custom enclousre is 8ft by 3.5ft by 3.5ft would this be big enough for a full sized nile and if too small would a savanh monitor fit in it my first choice would be a nile i am not bothered that they are aggressive or feed on live or feeding insects Please reply i realy want one...