Hi, in new to the jet boating would and just got my dad an old 67 Tahiti jet boat with a 327 Chevy. I am trying to understand the cooling system how it routes correctly, as i do not believe it is . it has log style exhaust and bypass thermostat. from what i find online (whitch its hard to find a good diagram) the inlet water from pump should go to a relief valve to a tee and go to the logs to preheat the water and then to a tee to the block and upper bypass ports the bottom ports go over board or to in to the exhaust. I think i understand the system but if i understand it right why do people run headers as the engine would never get to a good running temp and there would be premature ware on the engine let alone loss of power from running cold. Are running headers just to look cool? I thought i had a better picture of the cooling system sorry. thanks for the help!