Considering running 18’s - what fits?

[Nick_R_23]

I have a 1986 GMC C1500 LWB that’s lowered 4.5/6” on stock rally wheels. I ran across a decent deal on a set of 18” wheels that may potentially fit on the truck. It has 235/70R15’s on it now, and the new wheels would be staggered, but I’m waiting to hear the exact specs on them. The tires are 245/55R18 and 295/45R18, so diameter would be very close and I know the widths would be a sure fit. For those of you that have went the 18” route, what specs did you end up with for your wheels to fit? I don’t want any modifications or rubbing.