Running mostly distilled water .... check!
Water wetter ........................... check!
Radiator clean .......................... check!
Verify fans working ................... check!
Verify thermostat ..................... check!
Belly pan removed..................... check!
Rear engine compartment seal removed ........ check!

I'm left with a failing water pump or insufficient radiator capacity for my current horsepower.

I've asked Rob about methanol injection and he told me it wouldn't help with my problem.

So, out of all the water pumps out there, which one is best. I've found some cheap ones (GMB, Airtex) Bosch one, expensive ones (Graf, Laso, Saleri)

Les