[piecesparts]

The pusher fan is not a bad idea in some cases, but in yours it maybe just hindering your airflow that much more. I agree with the others, your flex fan appears to be way to small for the opening and it is hard to tell if you have it situated in the shroud opening properly. The fan blades need to be centered in the opening to ensure that there is no recirc of air back through the opening. That is the biggest killer in this install.

Ditch the flex fan and get back to either the clutch type fan or get a better radiator and put on an electric fan setup that is a pull type of fan. look for one that is made to cool an engine of your size and Horsepower.