I had installed a flat disc on the inpeller to my GMB pump years ago, supposed to increase water flow.
Like this: http://www.carcraft.com/projectbuild/116_9507_flow_kooler_water_pump_disc_install/index.html

The impeller does not look as good as the old factory cast iron unit impeller.
It had just a stamped steel impeller.

Maybe they are made different now?


MBHD

12 port SDS EFI