Emergency brake mystery

[Bern74]

Hi all
I am gettin to the end of the rebuild for my 1972 K2500 and need to replace the e-brake cables. All the parts guys told me they can get them at 39 inch or 41 inch..........as I put a small lift kit in I got the 41's but as it turns out the originals were more like 47 inch and of course the 41 does not fit.
Any suggestions on where to get the right cable or is there some alternative year that will fit??

If I can't get the e-brake working I won't be able to get insurance to drive it......help!