[67-ls1]

When blocking grill openings is it better, or does it matter, if I block the lower openings in my bumper and leave the main grill open or if I block some of both from the outside working my way in?
In my case it’s a 66 Chevelle so here’s a front pic.
I was going to block the two extra openings on either side of the licence plate. The area between the bumper top and grill bottom does have a filler panel in there it’s just black so you can’t see it.
Does it matter or am I over analyzing this?
Thanks