I've been told many times that the radiators with the plastic end tanks can not be repaired if the core goes on them. Well, I just found a small shop that actually has the machine to recore radiators with plastic end tanks. I gave him my worst radiator to try out last week. The deal was that if the end tanks crack when he takes it apart, he won't charge me anything, so I figured what the heck - might as well try it.
Well, I just got the radiator back and it's perfect! He used the original end tanks and top an bottom supports (he even was careful enough to keep the chrysler part number tag in tact) and made a custom core for it, and then he buttoned it all up with the machine for the crimped end tank pieces.
I have to say, it wasn't cheap, but if you are looking for a perfect original, this is the only way to go (unless Kelly finds another stash of T3 radiators somewhere...LOL).
Let me know if anyone has any interest and I can give you the info.
Jon