Isn't there already a box for it under the floor? If so, why would you go through the trouble of mounting something on the firewall?
Yes there is a box attached to the frame on the passenger side ,as original,but when I bought the truck ,it had a tray welded to the firewall which I took off for painting ,etc. I thought it would make a cleaner looking job to put it back under the truck if there were no issues with that. The truck will never be driven in the winter so salt is not an issue. Thanks