[nUcLeArEnVoY]

Don't pull your thermostat. Hell, if you're past the thermostat set temp, you essentially don't have a thermostat, anymore, anyway since it's fully open and will stay that way if you're overheating.

Running at 2500 sitting still will require a lot of air movement to mimic highway ram air. With stock gearing and trans, that's around 60 MPH. One good electric fan I've heard positive feedback on is the Flex-A-Lite #295 (116524) with dual 13.5" fans. It pulls 4600 CFM of air, but more importantly the shroud for each of the fans is slightly conical like what is seen on most modern car fan shrouds, and so it's not perfectly flat up against the radiator core like the terrible Cold Case ones I've heard about.

Sounds like it's not a water flow problem, either. Your pump is clearanced, and a Milodon pump is a good pump.

Ultimately I think this is an air movement issue. Either upgrade to a better e-fan, or use a clutch and proper shroud.

And of course timing. 16 degrees initial should be plenty, though. Are you using vacuum advance to achieve good cruise timing? A V8 will happily cruise at that RPM (2500) from anywhere between 48-55 degrees total with vacuum advance added in.