Uh, I have my heater hoses running the opposite way, ie: my heater outlet goes into the back of the head and the inlet (drivers side) from the t join near the bottom of the rad at the front of the block. I am SORE after reinstalling my heater today ( lotsa weird contortions to put it back in) but it all works a treat so far. I wondered for a while which way it was to go back but this is the only way I could make it work and thought it must have been that way to begin with, Would this make much difference?