1968 Airbox rebuild question

Again, thanks a million. I thought about some type of lube, as I stood there looking at the piece I just broke, and my life flashed back to when I started this project (was I 4 or 5?) frustrated that a heater core had shut me down after so much work. Come Monday, I will follow your advice. I've got to find a 4-leaf clover before cutting the grass. I have a rabbit's foot too

No worries! The best advice I can give you is to take your time, go slow and don,t force anything!
These parts are over 50 years old after all and most haven't moved from their original installed location after all this time!