I got my Caltracs last week also for my GTX build. I went with neutral height and am really wondering if I shouldn't have gone with -1" I was worried that the 30 inch tires would rub on the the top of the wheelhouse. In retrospect we are tubbing the wheelhouse to fit the tire anyway.

67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......