What year(s) are you talking about? Most of the "Big Bolts" do use the same cab,regardless of the years,but the fenders,and in some cases,the hoods may be different. I've seen "Big Bolt" (front)fenders used on some 1/2-1-ton 4X4's,but 1/2-ton fenders'wheel openings would be way too small to acomodate the 20" wheels. Hope this helps.
