justjohn -
I agree with Domman56. You can block the top grille, and maybe even the top half of the lower grille. If you use carboard for testing, you can just rip it out if it gets too hot.
I may be wrong, but form the pictures, it *looks* like you can stuff pipe-insulation tubing into the front of the lower grill. Some people do that because :
- It's cheap
- It's dark, so at a glance you don't "see" the mod in slots that are supposed to be dark
- It's easy to yank out if you are running hot
You may have vertical slats in the lower grille, so it may not be as straight-forward as I am describing. I am thinking you can cut a length of tube and stuff it in horizontally ... googling ... Ok, you do have vertical slats that are pretty close to the opening of the grille, so tubing may not work as well as I thought :
CarloSW2