1/8 Scale Truck Bodies
From what I have seen, there aren't any! What I would recommend is find out the wheelbase of your truck and match it to the body style you want. You may have to do a liitle searching, tho, for a 1/8th scale.
Most trucks have about a 12" wb, but you can get away with a body with 11"wb.
HPI & Atomik (tower hobbies) make a couple that fit the bill. Tho, both are Ford, one is an F-150 and the other is an F-350.
Don't feel too bad, I'm looking for a Dodge Ram....one that looks realistic, that has at least an 11"wb.
Hope this helps