I know this has probably been answer before but I could not find it. Im looking at doing 18" wheels and tires on my 1970 nova. Its completely stockwith no modification to the rear tubs. I would like to know whats the widest rear 18" wheel and tire I can put on the rear of my nova. And als0 owhat back space I need. Also what size for the front? I have qa1 coil overs and willwood brakes in the front.