3.9L EFI coolant leak out of clutch drain

Hi there, just spent the day packing my oil pump with petroleum jelly and a new gasket on my 3.9l efi engine, new filter, new oil pickup pipe gasket, new sump gasket. All in hopes of getting this this running properly, previously missfired a tonne and barely idled or increased in revs, been through many things now to oil pressure for hydrolic lifters. After everything done today, i know i have oil pressure and it idled smooth for the first time since I've owned it, but still no massive rev increase when using throttle, then it started smoking/steaming a fair amount from underneath somewhere (i thought was just oil on exhaust from oil change) but then also i heard a massive leak under the truck and there was coolant pooring out of the clutch drain plug??!! What... any suggestions? Never seen or heard of this before. Screenshots of the videos attached, it won't let me upload videos

Great well thanks for the help guys, i've gone elsewhere and its engine out for presumed core plug corrosion. Cheers