66 Conv/L6/Auto- Heater box crack... fix?

[bandit2]

I was replacing the heater core & hoses when I noticed a crack in the heater box collar. What is the best way to fix it? ... glue or something else?
http://members.cox.net/steel3rivers/IMAG0860.jpg

What is the best way to clean the foam and rust from the inside surfaces... before I use adhesive to put on the new foam pieces?
http://members.cox.net/steel3rivers/IMAG0841.jpg

As I was installing the new defroster hoses on the plenum, one of them ripped. How should I fix this so it stays on securely?
http://members.cox.net/steel3rivers/IMAG0816.jpg

 

[2+2GT]

It's basically fiberglass. Anything you'd do to fix a boat will repair it. Carefully done, the repair will be almost undetectable.