I would use harnesses that are made for you car. These guys are one of the best when it comes to Chevelles. You can have them modify a harness if you are running HEI dist or a mini starter what ever you need etc.
http://www.wiringharness.com/
Look in the upper right had corner of there web page.
http://www.wiringharness.com/
Look in the upper right had corner of there web page.