This is kind of an extension of another thread that I didn't want to get to far off topic so I thought it best to start a new one.
Like most of us, I have a real concern for the safe operation of our Classics. Wiring, Brakes and Reliability are some top issues.
Here is a site with lots of good stuff. It is mostly an EFI site but worth a look around at the tech stuff and products.
Here is a handy chart on Wire Gauge Sizes to use.
Also "How To Solder Like a Pro"
Battery Cable/Mega Fuse Assembly Solder
The bottom photo on that page shows the Mega Fuse wire completed. This is even more heavy duty than Dave mentioned and may be more than some need but it can't hurt to be extreme with some of this stuff.
In my case, my wiring is even older than most of the Birds here so I will opt for overboard.
Consider High Power Headlights, A/C, Electric Fuel pump, Auxiliary electric cooling fan. Some or ALL of those will be a real strain on the system. Of Course Relays are a must here also.
Side note on the Ford 3G Alternator - They are up to 130 Amp on such as Taurus and some others. There is also a large case and small case. The large has better ventilation and cools better. New after market ones go even higher amps. (That Heavy Duty cable is looking better all the time)