I did my 51 2.5 inches and did not have to 1/4 the roof I laid the A pillers back so I did not have to lengthen the door window tracks. You are going to have to 1/4 the roof to get the front to line up with that much chop. Go to webshots and search for mphracing one word and look at mine. It may help in some of your questions.
Mike
Mike