After you spend 10 hours of your life removing the aluminum glue and plastic heater core that failed you, you may want to upgrade to a copper, brass and steel heater core. It'll last a lot longer than your patience.
This is made in the USA of copper brass and steel.
A vertical baffle bisects the tank to create the same flow path of the OE design.
The 11 fin per inch and the 20 fins per inch is made to order.