Is there a way to widen a rear end housing?

im wondering if its possible to widen a rear end housing? its a fab 9 under a duster. when my dad had the car built, it was fitted for 14 x 32. the car has 31 x 10.5 w on a 14 inch wheel. the car still has full interior and in street trim. lights etc. i want to make the car look more of a street car. 10 or 12 inch wheel with 28 x 10.5. i dont really like the big tire old school look. trying to post some pics. let know what you think.