The slant has a single drain plug, 3/8" NPT on R side. I put knock sensor from a Chevy 1985-95 V-8 there (w/ 1/4" NPT bushing) for later use w/ an engine controller. No fan of the old Prestone flush kits which install a tee in a heater hose. I flush a few times w/ tap water, then add 1 lb citric acid and drive for a few days, drain flush fully, rid all water (w/ heater core change), and use Evans Waterless coolant for no future corrosion worries. I change all 5/8" hoses to silicone. Did this in all my vehicles, even 2002 Chrysler T&C w/ rear heat. No more coolant issues or worries.