New wiring harness

I have a new Ron Francis complete wiring harness with an 18 circuit new style fuse block and breaker panel to install in my '67 Satellite. Has anyone done this, and any sugestions about the hole in the firewall from the original harness connector? The car body and paint is all newly done, and the original wiring is all brittle and cut up, so new is needed. Thanks..
Author: satellite67