Bracket Car Wiring Help

Crackedback diagram in this post: questions about battery disconnect wiring

MSD heavy red should be connected to the battery/alternator power circuit.
MSD light red is the on/off. It should be connected to the key or switch on run.
If using a one wire alternator (no external field power) it could be also be tied to the kill switch.

Re: colored wires. Wire barn is a pretty good source. Some marine supply centers sell by the foot. That's another good option.