You spill anything on this mount, you're upside down.
Of course, that is entirely possible......
I took a piece of thick gauge sheet steel, marked, drilled and tapped it to match the screw holes in my bracket.
Plus a couple of other holes.
I laid it on my headliner, which is very thick and strong in this truck, and marked and cut all the holes.
Then I cut a slot and slid in the wide piece of steel with a couple of strings tied to the off side.
I slid it in all the way past the slot, and then pulled it back into position.
Put a couple of countersunk screws up through the headliner into the spare tapped holes to hold the plate in position in case the bracket was taken loose.
Mounted the bracket using the tapped holes with countersunk screws.
Put the radio in the bracket up tight against the headliner.
Mike bracket mounted on two screws on the side of the radio.
Antenna wire comes out of the back with a right angle PL259 and goes up though the headliner.
Across the top of my head and down through a space behind my left shoulder. The antenna is mounted on the tool box right behind me, so the wire goes out the back of the cab and straight into the tool box with a slight drip loop.
Never had to take the headliner down.
Power and ground goes up the same way the coax goes down.
Wanted to add:
The speaker is on the bottom as you can see, so it sounds good, and later I redressed the wires on the back.
After I got it all mounted and looking good, the final crapped out, and I had to take it down and replace it with a beefed up final.
I reinstalled it at the hunting camp, and all I had was some 3M wire nuts to rehook the wires.
After hunting season, I solder spliced and heatshrunk the connections.
