1972 K20 rear parking brake cables

[lutjanid]

I am having trouble finding replacement rear parking brake cables. All the usual places have either 39-9/16" or 41" (AcDelco part 18P2301) cables. But these are too short for my truck, which is stock as far as I can tell. The old cables measure 46", but I haven't seen a 46" cable listed anywhere. Maybe the mounting clip is not in the original location. Also, the intermediate cable is 85", which I have not seen anywhere. All the intermediate cables seem to be 116-3/8" (AcDelco part 18P2305). Has anybody else run into this? I know I can get a custom cable from Inline Tube, but I can't figure out why I can't find this off the shelf.