I was told by a old lead filler guy that back in the day these trucks did not enjoy the consistancy in construction that parts do today; at the factory they had piles of doors, hoods, tail and lift gates that had to be hand fitted to each truck. The camber (curve) of the body didn't always match that of the doors for example. They went through the piles until they found a 'best fit'. I have seen poor fit on '67/'86 Chevy/GMC doors from off-shore suppliers.
If your door is off that far you need to measure the overall dimensions of the door and compare it to the door opening dimensions,you should have 1/8" to 3/16" or so clearence. I would also compare it to a known good door to see if there is a difference on where the hinges go into the door. If it's not the same that's where your problem may be. If the door is ok then you might modify your hinges so you can raise the door by removing a 1/4" off the top edge of the door side top edge of the hinges and adding what you removed back to the 'lower edge' of your hinges. I would see about manufacturing a new off-set door side of your hinges.



1999 GMC Yukon
1957 GMC 100 Panel