You can buy trailer wire cable to run wiring to the back of a car. Its fully insulated and contains up to 7 wires.

Automotive Wiring 101 Basic Tips Tricks Amp Tools For Wiring
Hot rod ignition wiring diagram. Simple starter wiring diagram. Based on the above wiring diagram you need the following. If used for 6 volt make all the wires heavier by 2 gauges. Ok so lets get to wiring. Wiring up the starter motor circuit is rather simple. Read about wiring basics learn how to properly wire your street rod with all the tools equipment and everything else you need to know to wire your hot rod yourself street rodder magazine.
Hot rod wiring diagram please note. All advice and instructions are intended to be basic guidelines and not intended for use by individuals who are not experienced in that field. Ignition switch the starter is turned on by the ignition switchs sol solenoid position. The easiest one ive found to be useful is in mike bishops book how to build a traditional ford hot rod page 121the diagram included everything i needed when i built my first roadster with exception of an ammeter amp meter. See the lighting diagram below tip. All content in the articles in this section are the property of the author of the article.
For example 14 gauge wire will become 12 gauge 10 gauge will be 8 gauge etc. Just make sure the gauge is ok for what you want. So use the right size wire. Wiring always frustrated me even the simplest layout can be confusing. It doesnt have to be on the key switch you. It is a momentary contact position usually on the key switch.
This diagram was designed for 12 volt systems but can also be used for 6 volt systems. Its cheap by the foot and protects the wiring from any cuts wear etc. Return from hot rod wiring to how to build hotrods important notice.