Can you pull up the original thread on this for more background info. As said I would confirm the actual temp with a known good gauge or infrared gun what ever it takes. Assuming the initial ain't severely retarded which I doubt it is & with a new stat/pump I'm thinking there's plenty of water flow UNLESS the rad is severely plugged & I doubt the lower hose is sucking shut at idle. sounds more like an airflow problem but you've addressed the fan but might put a shop fan in front just for a check to see if it is an airflow issue & can you feel the air being pulled thru on the front side of the rad?. I would take off the water pump fan belt & the stat housing & the stat & with the coolant at the brim, start the eng from cold & gun it repeatedly for a minute or two max & see if there's bubbles or if the coolant starts to rise which it should not rise in that length of time starting from cold since the water pump is totally diasabled there should be a dead calm with no turbulence unless there's a combustion leak. Keep us posted. #1 confirm the actual temp. EDIT hitting 250 in 5 or 10 minutes tells me there's a severe issue going on