You can go to a 15" or 16", if you can find them. The problem is the setback, the distance from the back edge of the rim to the flange. I'm thinking the minimum is 3-3/4" so the tire will clear the tie rod ends on the front. If you don't care about the hubcaps, there are some Dodge rims that will work. GM went to a deeper backset, and I haven't been able to find anything close enough to work on the front without big spacers. On my rears I have rims off a 93 with 7.50R16s, there is about an inch between the tire and the frame. Still running 15" lock rings on the front, I might end up machining a 2" spacer for them. If you stick with a GM rim, you can transfer your hubcap clips and run your stock hubcaps.
