Starting gremlin

First, a huge thanks to all of you who take the time to post thorough, detailed and very helpful posts. I have successfully rewired and worked through my entire ignition circuit and never even had to post a question. I did it all by searching old posts and solved my over-charging issue and a few other things that were hacked up by the previous owner EXCEPT this one...

(65 cuda, 5,2 magnum, electronic ignition, NEW solid state voltage reg, alt, batt, mini starter, starter relay)

Sometimes, and ONLY sometimes when I turn the key to start, it
1. clicks continuously - like the classic bad/stuck solenoid sound
2. sometimes just clicks once and then - nothing
3. Every time this happens my GPS that is plugged into the lighter socket goes dead, meaning that the power is getting cut somehow.

What I discovered is if I unscrew the quick disconnect on the bat and then snug it back down all is well and it turns right over. No exceptions, it 'fixes' it every time. Just to clarify, the GPS loses power before I disconnect and reconnect the batt :)

I'm baffled. Any ideas ?

I know that someone will say that just because it's a NEW part doesn't mean it's a GOOD part but this symptom has remained through all phases of engine swap, part changes, new ignition circuit, etc... I swapped old parts back in with no luck.