Hi Monica...Firstly, Welcome.
I don't think the gap should vary hugely,there is only so much movement the bolts will allow.
Basically I've set mine up with the front bolts(nearest the cab)
vertical and I reckon without measuring, it's about 1/2 to 3/4"
at its tightest.
Bearing in mind the beds front panel is flat whereas the cab rear has a slight bow.
I'm not sure if there is an exact amount,but if there is,someone will chime in soon and say!
Remember,factory tolerances weren't as critical 50+ years ago.
BTW go to the message board and introduce yourself to the 'gang'!
P.S. Post some pics too.
Jock
