I'm thinking about trying to repair the plastic interior panels on my 68 Dart convertible. Reproductions are very expensive.

First of all, are the panels made out of the same plastic as the E-body L/R lower dash trim? On my Challenger, I was able to heat up the right hand lower dash trim and move it slightly to better fit the aftermarket dash pad. Can I do this to the convertible panels? The leading edge of one panel is warped where it wraps around the lip at the back of the door opening. I was hoping I could heat up the area and move it back into place.

Second, how should I go about fixing cracks and pieces missing? One panel is in decent shape with only a slight crack in the sill plate area. The other has a chunk out at the top. I have most of the pieces that broke out. How would I go about reattaching them? I assume I need to reinforce the area on the back side? I was thinking that the broken area will be partially hidden with the top boot installed.