1988 5.0l heater core problems
 

My heater core blew so I changed it on my 1988 5.0l mustang and in 4 days or less of regular driving the new heater core already blew up!!! (it was an after market replacement)since the heater core being as simple as it is I am assuming the new one was possibly defective?? but what would cause 2 heater cores to pop in the almost the same place ( right side inlet at the bottom of the tube) I need some help here guys before I go and spend another day ripping the dash out.

do yo uhave a highflow water pump? if you do it can cause to musch pressur ein there and blow them out. you might need a pice of pipe in the feed line for the heatcore to slow the coolante down a bit.