"Home-Brewed" Battery + and - Terminal Blocks Finished Photos Added

You guys and Dave/ Kit have brought MORE thoughts. "In the case" where you guys have A TRUNK MOUNT battery with and even more special WITH SEPARATE GROUND WIRE from engine block to battery here's what seems to me:

The entire length of battery cable.........that is, from the starter terminal, back to the trunk to the battery, and back up front to the battery block IS AN INDUCTOR

This means that every time you engage/ release the starter, that inductor (such that it is) will produce a certain amount of "spike" in that length of cable.

So if the loads in the car are grounded at the "up front" points on both ends, that length of main cable is going to impress whatever spikes it generates across the loads.