51 chevy truck door trouble

[garyt]

i am in the process of adjusting my truck doors and i get them perfect, everywhere with a good fit except where they meet the top rear of cab. there is a radius on that part of the cab that just doesnt and wont fit. and it happens on both sides, before i take a grinder to my doors am i overlooking a more obvious fix ? its as though my cab has either moved or has sagged over the years because it is on both sides and these are the original doors on the truck...any suggestions would be much appreciated thanks garyt