Donny knows more about old cars than I do.
I owned a whole bunch of (ten or twelve of them anyway) 1955 Chevys, About two thirds had a SBC and the rest a 427, but all of them had my own personal wiring as I ripped out all of the factory wiring and replaced it for a heavier gauge with circuit breakers. I did this because my 409 powered 150 two door sedan '53 Chevy nearly burned to the ground because of overloaded factory wiring.
I probably should have done the same to my '61 Corvair with its quad Lucas "Flame Thrower" matching rectangular driving and fog lights but I had them on a relay to a second battery kept in the trunk to power my stereo and added lights (because the tinny factory battery location was in the back of the car with the equally tiny generator).
I did this because I was working after school at my Local NAPA jobber and got all of my parts at cost. A spool of 14 gauge wire cost me the same as a spool of 18 gauge wire, with 10 and 12 gauge costing the same so I up scaled everything. Even using six volt battery cables for the 12 volt ones because they were huge by comparison, and not much more back in the days when there were still cars on the road with a six volt system.
If, as Donny say there are circuits that are unprotected I recommend adding a 40 Amp circuit breaker that is soldered into the line as it exits the positive terminal (main feed wire).
It is a much better way of protecting the car from an electrical fire than what the factory used from 1967 and up which is a fusible link:
The Chevy fusible link is covered with thick foamy red plastic insulation and can be easily found by the two black plastic ferules at the beginning and end of the ni-chrome wire.
I know Copper has gone up in price since the sixties, but I believe that heavier than stock wiring is required if youi are going to add two to three times the electrical load than the factory engineers anticipated.