One of the hood latch cams rattled off on my 1983 310 and the threading for the screw was all stripped out on both latch assemblies. I read a post about tapping the barrels for a wider screw and just my luck, my tap broke off when it bottomed out. While attempting to extract the tap, I trashed the barrel, which is made of weak pot metal. I looked all around and couldn't find a good replacement for the hood latches. I tried a few cheapo sets from amazon (Camco and "RV Designer Collection") and neither was the right length and both were very poorly made. I did find a post here from a long ago that mentioned a company called Southco made the original latches with a link to a dead website. I searched Southco and found their new website and was able to track down exact replacements for our old rigs!! They are very well made and feel like they will last as long or longer than the originals. They set me back $38.83 including shipping.
Here are the part numbers:
Cam Lock Latches
Cam Lock Cam, Steel, Zinc plated
And here is their website:
I'm not sure what years they are compatible with, but if you have the metal thumb latches that turn 90 degrees to latch your hood, these should be them.