Wheel size is limited at best. Ground clearance is probably as good as most small block headers. You don't have a lot of choices on manufactures. I use Hooker super comps.
If you can get pass cutting the inner fenders then fender well headers are great. They flow good and give you ample room around the starter and trans. Easy to change plugs and on a B engine they clear the master cyl by 2or 3 inches.