68 Heater core Barracuda

The foam could prevent a vibration noise and/or prevent air whistling around the core.
I think most any glue would work at case repair. I like Devcon Home 5 minute epoxy for it's 5 minute work time and low odor. Some of the 2 part epoxys really really stink !
This case might be a good place to try that new UV light activated adhesive.
Walmart has 5 Second Fix brand on their "seen on TV" shelf ).