Is it legal to box in the radiator so all the air entering through the grill goes through the radiator and doesn't escape around the sides?? Don't see any mention in the GCR

"Any radiator may be used, provided it is mounted in the original location, maintains the same plane as the original core and requires no body or structure modifications to install."

So does moving the radiator 3 inches to the right and drilling two new holes count as legal or illegal?