I had a radiator that was beyond repair. The radiator shop took the measurements of the core and ordered it. I was charged $400.00 for rebuilding the radiator and core. This included boiling out the gas tank and putting a sealer inside the tank. I just talked to the radiator shop and they said the prices went up on copper.
Yikes! $600 bones?!??! Call these guys:
They don't list Imperials, but they list other Mopar big block cars and likely could make you a new one for well below that price.