i know the two nipples circled in red are for my heater but i'm not sure which one is the supply and return. one goes to the water pump and one goes on the block or somewhere on the intake i believe. also went from c to w block, will there be any differences? if so, what? can i use the bypass nipple off of the thermostat housing as one of the connections? hope you can see whats going on in the picture.