The 68 400 I rebuilt was hot running before I reduced the impellar/divider plate clearance from about 1/4" to 1/16". It's not on the road yet, but it stays at 180 whether at fast idle or curb idle. I even blocked the radiator to let the temp get to 220. It went right back down to 180 after I removed the blockage. So far, so good.
