I run 36x12.50x16.5 Super Swamper TSX's on 8.25x16.5 wheels on my '78 W150 shortbed stepside with no lift. Fenders cut and inner fenders trimmed. No rubbing on anything. Just watch the wheel offset to keep the left front from rubbing the drag link.
My '85 had a 2 1/2" lift, same tires and wheels and trimming and it had rubbing on the drag link.