Making progress mounting stuff. Got the feed thru box done and installed with clecos. Started work on the panels that hide the back of the cab. The one on the passenger side will double as the mounting surface for the stereo amp, etc. Failed to label everything years ago when I took the components out of the truck that became the Silver Streaker so now I have two options... take it to someone that knows what they're doing and have them wire it up or do the Google. Early search results lead me to believe the Zapco / MB Quart pieces were nice (back in the day) but are now pretty much obsolete. Most semi-relevant threads are around 10 years old.
