Thank you very much for your kind words for my car. I did spend quite a bit of time and effort to cleanly route all of the spark plug wires and all of the engine compartment wiring, as like you, it bothers me if it's messy.
You are correct regarding my Coronet having it's battery relocated in the trunk compartment. It's located over on the right side of the trunk compartment and I did this conversion back in 1991 or so by using one of the Mopar Performance battery relocating kits. I believe that the current part number is still P4349500AB but this kit is a little different now than it was back then as it looks to include a battery box in the kit now that wasn't included back then. I also made some modifications to the original kit by adding the following upgraded parts.
(01) Installed upgraded N.H.RA. legal (at that time) 3/8" inch threaded battery hold down j-bolts
(02) Installed upgraded battery tray to trunk floor mounting bolts, nuts and washers
(03) Installed a custom made heavy duty battery hold down strap
(04) Installed a custom made N.H.R.A. legal (at that time) aluminum firewall to replace the original factory cardboard divider that hangs on the X brace located between the back seat and the trunk compartment
(05) Replaced the Mopar Performance positive and negative battery cables that came in the kit with solid copper welding cable
(06) Installed an N.H.R.A. legal (at that time) external electrical system cutoff switch under the passenger side of the rear bumper.
(07) Installed heavy duty quick disconnect terminals on the positive and negative battery cables that fit the upgraded solid copper cables
Here's an older picture that I took of the battery set-up years ago, but if you need better pictures I can try to do that for you with my digital camera. The solid copper positive cable is run from the battery down through the trunk floor to the appropriate side of the electrical system cutoff switch and then back from the cutoff switch back into the trunk compartment up to to the front passenger side of the trunk compartment, then over to the drivers side of the trunk compartmen and then into the main body wiring tray trough on the drivers side of the car. From there out to the battery relay I don't remember the exact route that I ran the cable, but I'm sure that I found an existing hole as I don't remember drilling any holes. The negative battery cable is simply run from the battery over to a major metal brace on the passenger side of the trunk compartment.
I took this picture during the cars restoration back in 1991. It shows the X brace where the custom aluminum firewall that I made was placed. This is also where the positive battery cable came through from the trunk compartment into the interior compartment and then into the rear and main body wiring harnesses trough on the drivers side.
This last picture shows the electrical cutoff switch mounted under the rear bumper.
Richard