Just saw your post. I have a 70 Challenger with a 383-4 bbl with AC. On my car when looking at the water control valve from the radiator side, the upper outlet is 1/2. When looking at the top of the water pump housing, the outlet closest to the carb is 1/2. The other outlet on top of the water pump housing closest to the radiator is 5/8. Both outlets on the water control valve on the firewall side and both heater outlets on the firewall are 5/8. Hope this helps.