Do you mean that the tubes from the rear of the manifold to the front would lower the temperature at the back of the heads?
Because if you have a 16 pound pressure cap on your radiator, your going to have 16 lb throughout the system I would think.
Having a "water pressure" gauge is the trendy thing (I guess) around my area with the oval track guys. My kids B mod has one... The PO made it sound like it was a necessity to race... I guess I'm too dumb to know stuff like that.