Bracket Car Wiring Help

Pretty simple figure out if you want the starter battery cable hot all the time or not.

If you want it cold when not starting and depending on amp load, run a 2-6ga single cable forward from the cutoff switch feeding the fusebox/switch box... DONE! Branch anything else off the fusebox or buss point up front. No alternator makes it simple.

I hook MSD's up all the time on a buss point that has a well sized feed cable. Never an issue.

If that switch box has relays in it, great. If not, I'd set up a relay gang to run all those components and keep the load away from the toggles.