Re: black factory fender flares
I do not think that 31's will fit without any lift. My brother's truck had the 3" Superlift, chrome trimming around wheel wells, stock wheels, and 31x10.50R15 mud tires. They would rub while wheeling. Your 30's should work with the black fender flares. You can crank up the front torsion bars some in the front (although you should get the front end aligned after this) to get some lift. Then try some air shocks, helper springs, or longer shackles in the rear. I'm assuming you still have stock offset wheels. I hope this helps.
'85 longbed, 3" Superlift, 1" body lift, 30x9.50R15 Courser OTD on American Racing AR8 wheels.