47's are tall tires, and a lot of rotational mass, your going to need gearing, if it is just a mall crawler and no off road than run them. The 99 newer SD have a metric bolt pattern, 8x6.5 will not fit. You will have the deal with the offset of the rim, which is one reason why your tires rub now, Not sure what brand of tire your getting, bias ply, radial, don't know how they will balance out. Might be a rough ride, might have to lift the truck up higher to clear. It's your truck, but IMHO, 47's are to much for stock axles. Stick with 42's or go with 44's.
I take it military tires than. Not saying the rims are wrong, you can get different offsets in rims. in my thought you will need less backspacing which moves the tires out further away from the knuckle, extra stress on the bearings/hubs. 15" are wide tires. My new tires I am getting are 44x19.5 wide.... not on my SD though. Not sure what bumpstops are going to accomplish??? If your tires rub on the leaf springs than get wheel spacers or new rims... If they rub on the fenders well either cut the fenders and install bushwacker fender flares that open up the wheel well openings. or lift the truck up higher. just offering my .02
The newer superduty's use a metric (8x170mm bolt pattern) if I recall correctly. 8x6.5 will not fit that is a standard bolt pattern. like chevy's, dodges, older fords. I don't know what the rims came off of. What were they off of when you bought them?
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