the ranger blower box is really big, and if you are running 20's or bigger w/ a bodydrop I don't see any way it will fit. I removed everything from the manifolds out on both sides of the motor for clearance.
I am looking into running something like this. you can pick one up for around $200 and it is only 10" x 9" x 5" so it would fit under the dash easily.
http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=94305