Lesson learned. I had a heater core replaced that I originally intended to do myself. I got to see that it was going to take quite a bit more effort than I had time for so I took the heater core I bought and had Jeff's Auto put it in. Unfortunately the heater core was defective and 300 dollars I paid to have it put in was for nothing. If Jeff's had supplied the heater core it would of been a free replacement on the defective core. Since I supplied the core the bill was on me. Totaling with both cores and labor I had to come up with over $700. Not what I had in mind and an incentive to keep doing my own repairs.
I do not fault Jeff's Auto for what happened as they did a good job and quickly as well. It was just my bad luck that the heater core I had bought was defective. If there is a next time I have someone doing repair work I will just eat the jacked up price for parts that most shops charge and not have to worry about paying for the job twice if the new part is defective.