Aloha & God Bless You =)

I was reading a post from Walter Jr & according to him & my calculator the year 2241 according to our calendar will be the year 6000 in the hebrew calendar but I was wondering about what is the difference from the regular reckoning & the fall season reckoning because I heard a doctrine that made sence a long time ago but the date was wrong - I heard that because of the passage in peter that says a day is as a thousand years & a thousand years is as a day to God mixed with in the Revelation it says that there will be a 1000 year time of peace & you cross that over with Genesis where it says God worked 6 days & rested on the 7th & you come out with a doctrine that goes that 6000 years after God created Adam will be the end of the great tribulation & the beginning of the 1000 year millenial reign. But the date that the guy had was wrong because his calculations would have put the beginning of the revelation between 1996 & 2002 all of those years have past so I was reading in a book that the jews counted the years like there was still 300 - 600 left untill the year 6000 & now according to the calculator it is 241 or so years from now will be the year 6000; now if this doctrine is true the 2nd comming won't be in my lifetime, but the scripture does say that the days will be shortened for the elect's sake. My main question is did any of you ever hear this & what is the grecko roman year that will line up to the jewish year 6000 & What is the difference in the reckonings?