I initially did a Search on this subject and found very little usable material.
Then, I put in the words "door strikers" and found a wealth of information. I even found one thread about someone who wanted to do exactly the same thing that I'm doing: put '51 door(s) on a '53 cab.
Woody had a great thread and pics showing a '52 to 54 striker on a '47 to 51 cab. Woody used a shim to make the modification.
http://www.pbase.com/czechman/image/100876314However, the holes in the sriker don't line up with the holes in the post. The holes in the striker are inset, as you can see from Woody's pic, and don't appear to be modified. The threaded holes in the bars where the screws attach are held in place by a bracket, and are not easily moved.
I'm wondering what others did in order to rectify this situation?