Sorry I don't have any pics, but what I did was beveled one edge of the 1/8"x3/8" flat bar so you can lay multiple spot welds on the outside of the door. The flat bar is placed in a manner to extend the width or height of the door. Grind the edge of the door to your desired gap. Hopefully my explaination makes sense.
Like what was said about these trucks they were made for utility not for looks. I used doors from a pickup on my panel and the gaps were wider than the original doors. The assembly lines back then were manned by men/women not the computerized robots of today so things weren't quit as precise.

 

ok thanks no problem, I will try to solve it that way

 

DON'T adjust the door edge until the cab is bolted down to the frame with new mounts front and back. You'll be surprised how much the door opening will change. Looks like the cab needs to raise at the front mounts and lower at the rear mounts or pull down on opposite diagonals (depending on how the other door fits. Put a 1.5" block under the front mount and have someone stand or sit on the floor by the rear corner just to see how much it can move. If you adjust the door before you mount the cab you'll likely be sorry later.

 

AXracer is 100% correct .
Do not do anything to adjust the gap until it's bolted back on the frame .

 

thanks for the new councils, the other door is pretty well adjusted, what I wanted was to paint everything before mounting, and have everything adjusted to avoid damaging the paint, now I will have to mount, dismount and re-adjust