I just put mymagnet mount up when I'm running the intersate or long trip, then toss it under the back seat when not it use. I can't really bring myself to do anything permanent on this truck as far as a CB is concerned. I don't even mount the radio permanent inside. If I was going permanent, I would put it on the hood with a trunk lip mount, or bolt it to the bed rails with a Wilson 5000 or similar. I would think that going through the XM or Onstar hole would be a good idea though, I didn't really ever think of that. If I went that route, I'd drill the roof to put in a K40 or a 1000. You can actually take the main part of the antenna off with a simple twist and put a cap over when not in use, and it's a **** not much higher that the XM or Onstar.

 

Hi, Installing a ham/cd mag mount is easy on this vehicle. Use a heavy gauge of wire to connect to the battery. I used the wire supports on top of the firewall and wove the power wire around the supports and added 2-3 cable ties.

Do not connect the wire to the battery just yet - DON'T! Run the wire to the right driver's side firewall.
Before running the wire into the firewall I added fuse holders to the (-) and (+) wires. I used the push in type of fuse @ 25 amps.
These remained on the exterior of the firewall as extra protection.
On the firewall you will see near the top what looks like a large plug with the wire harness going into the center of it.. I used a long 12" pointed Phillips screw driver and gingerly poked a hole thru the protective plug above the wire harness. I checked in the cab.

I then used a small piece of pvc pipe with a 1/2 inch diameter and pushed it into the hold made in the rubber gourmet. I threaded the wire thru the pvc. The pvc acts as a wire guide and a wire protector against any sharp metal edges. It was/is left in the spot.
Under the dash, I ran this power line up away from the brake and gas pedals and down to the front of the trany hump to the wooden console I built where the 3 radios were housed. Done.
Adding an mag mount antenna to the cab's roof is easy. Under the driver's seat toward the back of the cab on the floor, under the rubber mat and insulation you will find a 1.5 inch plug. each side has one. I drilled this out with a 1 1/8th drill bit, leaving the rest of the plug on the metal edge of the cab. I then threaded the coax up thru the hole; under the seat to the console and radio. Check the swr 2-3 times to get it as good as you can.

Next I made a grommet from a piece of heater hose. Cut it down one side. Put it over the coax and into the hole. This protects the coax. With this done, I added rubber silicone on both side of the coax entry hole to seal it up. I also added rubber silicone to the small tube holding the power wire on the outside of the firewall.

Connect the radio and call up some close and distant repeaters (2 meters + in Ham Radio).
Works slick. This is how I did it. You make the decision on how to do it. I felt this way was best for me, sealed, low, low swr; nice clean cut install and operation.