If you are someone with mechanical skills, you might consider doing what I did. I knew the originals were well worn after 60 years use. I couldn't keep the drivers door from sometime swinging open while driving! Now I was seriously considering ordering some aftermarket latches. After reading some of the past post on aftermarket latches I decided to have a closer look at the originals. What I found was that the ratchet part with the teeth was worn down. I mounted the latch in my vise and removed the rivets that previously held the ratchet portion of the latch. Carefully filled in the worn down teeth with a little wire feed weld. Using the pass/side door latch as a pattern I re-traced the new tooth pattern on the drivers side ratchet. I easily refilled all the teeth back in. Re-assembled everything. Man what a difference!!! the door stayed closed and was fairly easy to adjust.
Hopefully this will help


http://www.classicparts.com/1947-51-Door-Latch-Left/productinfo/18-521/#.UvkjUmyYbIU

1951 Canadian Chev 1/2-ton Shortbox