1968 Airbox rebuild question

Having done this several times, I've been there! A tip for you. Clean up the heater cooler pipes down to bare metal with steel wool until you have a shiny surface. A light coat of white grease and those plates will slide over the tubes very easily!!
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