47-55.1 Cab to bed spacing

[mobileortho]

Working on shortening my 3600 and one thing I wanted to address was the amount of space between the cab and bed, to me it seemed like too much of a gap. Question is, how much is too close without hitting the back of the cab from flexing? I’d like to weld the nuts to the outside of the bed then cover them with the stake pocket and have the bed line up with the splash apron. It doesn’t really show in the pics, but that about a 1/4” gap.