[67-ls1]

The grill opening aligns with the middle part of the radiator. Roughly the middle 3rd. The upper portion is covered by the leading edge of the hood and the bottom portion is behind the bumper.
You can see in the pic below that there is quite a bit of grill opening on either side of the radiator core. I can block that and roll the block back to the core support.
You can also see that about half the bumper opening align with radiator. As an alternative I could just block the outer portions of these openings.