What is the stock OBS rim offset/backspace?

[crazy_canadian]

Hi,
I bought some Toyo MTs, 315/75R16 (35x12.5) to fit under my F-350 CCLB.
I am looking at different black steel rims, I want a 16x8 rim, and it will need to be further on the outside to avoid rubbing against the leaf springs.

What is the stock offset and/or backspacing of the stock rims? (16x7)
What offset should I get ?

Thanks!

[CT Performance, Inc.]

4.5" BS is stock and whats needed, offset never matters.