Posting for info only and to help others. I've fought high temps on my 440 dart since day 1. I'm blowing it all apart and redoing everything regarding cooling. Water pump/housing, radiator, fans...all new. There's been lots of talk regarding casting on the 440source water pump housings having smaller passages. Supposedly a manufacturing flaw that was corrected. I bought mine maybe 2-3 years ago. AFTER all the drama was fixed. Well...hard to measure, but I can tell you without a doubt there passages are smaller than the Mancini Pump Housing. in the 440 source passages my finger can barely wiggle. In the Mancini one...I have at least 3/16-1/4" wiggle room. Doesn't sound like much...but I think it's notable. Also feel like the 440source water pump design isn't helping things. Anyway...just info for the masses to help others make decisions.