67 Dart Resto w/5.7 hemi

Hey Lime, Hope you had a good Christmas, and I hope Santa brought you some goodies for that HEMI. I have a question for you, I'm finishing up my firewall, getting ready for paint, and I was wondering where you made your hole for the wiring harness, and how big? HotWire recommends a 2 1/2" hole behind the right side head, does that sound rignt? Do you have any Pic's?
Thanks.