Re: was offered cheap tires...
I think, not speaking from experience here, they should fit the rim fine. With that setup thought I would expect those tires to have some mild rubbing with the front tires, I think the rear ones would be fine. If you trim the bumper ends and mounts and pound down those fender seams, maybe you will be ok
Sorry I can't give you a definitive answer though.
If they are cheap enough just go ahead and get them, and if you get a little bit larger lift then you can just throw those on there.
88 Sammy in the garage