A '50 3100 would have Huck brakes, while a '51 would have Bendix brakes, so there's probably a difference on the back end of the cables. That being said, I went thru three different vendors before I got usable cables for my '51. First I went to RockAuto and bought AC Delco parts they listed, and those didn't fit in the frame clamp (too big), then I bought a set from the Filling Station - those didn't fit either. Finally I bought them from LMC Truck and they matched the originals and fit correctly. I see that LMC lists a "universal" repair kit
here but no longer list the complete cables for '51 3100's.
Attached is a parts listing for the cables. Note that there's a slight difference in length between '50 and earlier and '51 and later. But that's not significant.
Jim Carter lists original style cables for 3100's saying they fit from '48-'55.
LINK
