The rockers on the nova have a double vertical panel in it,, I cut through the first which is close to3/4" from the other panel,, This left the original piece to help support car on the jig !! It would have crushed the rockers,, I built a 69 camaro 5" ride height 5yrs ago and used 3x3 in the rockers & 2x4 for the frame rails,, but floor pan was flat, and not much knee room !!!! It was perimeter but the main 2x4 was straight ,on 28" centers,,, the 2x3 added structural rigidity ,,
