Very surprising about your evap. core leaks Rusty.  Both of my 70's vintage cores have moderate dents & dings on the segmented tanks but have never leaked.  Now they have only 30 psi coolant pressure but were tested to 200 psi w/ air before installation 11 years ago.  Had originally planed to use them only for trial fitting but since they worked, I got cheap and kept them.

 

Tracy