Here is a picture of my 51 1/2 ton firewall.

http://s1116.photobucket.com/user/1950Cabover/media/IMG_0699_zpszwbxfrmk.jpg.html?sort=3&o=21

Other than the windshield washer accessory with bottle and pump, I think you can see the holes for wiring, wiring clips and firewall pad clips. Does this help you?
Kent

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