You have the wrong cables. I ran into the same problem with my ‘52. The cables that came with the truck physically were too big for the brackets and were strapped on the brackets with cable ties. I bought new cables from LMC Truck and they fit the brackets perfectly.
Unfortunately, some of the cables sold from many of the venders are not correct for our trucks.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum