60-66 chev - gmc wiring basics

[62gmc910]

These trucks were first set up with generators, until 63 then an externally regulated alternator, these systems were only designed to run point ignition, incandescent headlights, a perminant magnet heater motor and maybe an am radio. The alternator was 37 amp so even at max out put it had trouble with those spartan accesssories. even in an all original truck running the fan at full with the hi beams on and maybe the radio the "gen" light glowed faintly.
Most of these trucks end up with newer internally regulated alts. most of these are at least 60 amp or better. the heater motors change up to the same stuff as the 90s trucks these fan motors are serial wound and draw way more power, electronic ignition has a 12 guage wire for a reason.
We are over taxing a 43 to 50 year old system just running nessesities.

My '62 has had the fuse box and primary wiring replaced with a harness from an eighty this was a fairly major under taking even though i knew what I was doing and our friends at GM had kept most of the plugs ETC the same size,
If I were to do it again I would
1) if the basic wiring was OK , just run the Ignition turn signals brake lights thru the stock wiring. The rest head lamps, fans , stereo, and what ever I would run thru a fused relay system fed from close to the battery/alternator
2) maybe try one of the replacement systems but these scare me, made in china?
3) find a decent after market fuse box and build my own
I 'am hoping this thread gets a sticky and we can expand on it as necessary I will draw a map of the relay plan as soon as I get a chance.