MG Car Repair: Wiring Harness, turn signal switch, captive nuts

Question
I have a 1973 USA MGB.   My winter project is to replace the wiring harness as the current one has been modified (chopped up) here and there.   I want to keep the wire color codes and so plan to buy one from advance auto wire.   I've already replaced the ignition switch, turn signal switch and horn brush.   The wipers are currently wired to a toggle switch on the console, so the wiper switch will be replaced as well.  My question is "Where is the best spot to install the new relay/fuse box block the new harness comes with?"  Also would it be best or wise to run the rear wiring through the interior of the car?   
thanks,
John

Answer
Hi John.  I would keep it standard.  There should be two captive nuts on the right side of the engine compartment, about 9 inches forward of the bulkhead and about 3 inches below the top edge.  They take a standard 4-fuse Lucas fusebox, mounted vertically with the two sidelight fuses at the top.  Note the link on the back of the fusebox.  If you mount the fusebox upside down it won't work correctly.  

The rear harness should run under the car, entering the boot compartment at the front edge and then running inside the boot.