For the grill block I used paper, a crayon, masking tape, cardboard, duct tape, and toggle bolts to attach it.
So I started with many pieces of paper taped together and the crayon to get a "print" of the front grill.
Next cut out a piece of cardboard to get the rough dimensions.
I had to leave the Ram exposed for style
I then whittled away at the cardboard till it was a exact fit. (or so I thought) Then I wrapped the cardboard in silver duct tape to help strengthen it and mild waterproofing.
Closeup
As you can see from the closeup that the edges don't quite go all the way over. Having the cardboard wrap around the center grill beams shrunk everything. I meant to do a full block but then thought I should have some way to reduce it if needed. So I cut it off at the bottom so I could make a second piece to be able to come off if I needed more cooling. Well the second piece didn't fit and my mounting method required longer screws so I abandoned it.
I plan on making a new one out of chloroplast that I have if this works. So far it has. Warmup in the 40s-50s F is quicker. I am running a tank through currently to see how it ends up.