Found some 17x9 Cobra R rims and 275/40/17 tires on Craigslist for cheap. We wanted a bigger footprint for the road course .. it was just a matter of fitting them!
Fronts fit fine .. just needing to remove the upper ball grease zerk. On the rear, we removed the 8.25" corporate rear in favor of a '67 B-body 8.75". The rims had almost 6" of backspace, so we needed the wider housing, and offset hangers to relocate the springs in .80".