[Denis]

I'm no expert but I recently installed a pair of restored kick panels in my 67 car, seeing as how a previous owner had also fitted speakers into the original panels.

On the passenger side, I had to first remove the heater plenum assembly. You might be able to force out the old kick panel without removing the heater plenum but you'll find it next to impossible to put the kick panel back in. Also a good opportunity to check your heater core for leaks or corrosion, or maybe to install a new set of seals.

On the driver side, you need to remove the high beam floor switch and move the parking brake assembly out of the way. To move the parking brake ass'y out of the way, try first removing the single screw that bolts it to the underside of the dash. If you still can't remove the kick panel, you will have to loosen or remove the parking brake assembly's nuts on the engine side of the firewall. You shouldn't need to disconnect the parking brake cable itself.

If you're really anal (I know SS427 is lurking out there), there's a place where you can find gray replacement sealant that matches what the factory uses to seal around the backside of the kick panel duct. The product is called Permagum and it's used by the HVAC community to seal refrigerators and air conditioners.