cab swap question

[Billy Bad A$$]

Hello, i am doing a cab swap on my 69c10 with a 68 high hump cab. I just took off my front clip yesterday and i noticed one huge difference between the two cabs. I noticed that the fuse box location on the firewall was different and the fuse block on the 68 cab is horizontal, unlike the vertical one on the 69 cab. my question is i want to keep the wiring from the 69 cab and put in the 68cab and also the 69 foot parking brake i would like to put in the 68cab but the firewalls are different, has anyone here ran into this and what did they do to the cab to put the 69 and later foot parking brake assembly in? any info would be greatly appreciated.