Actually, on a six cylinder #1 is closest to the water pump and it runs too cold (and too lean) if the water flow is too fast or there is no shield on the pump impeller.
Are you using a thermostat, strayfarer? If you aren't then you are getting too much water flowing through the pump and overcooling the #1 cylinder. This affects the clearances a lot. If you are running a thermostat (180 or 195 degree is best) and your engine is running that hot then you need a new and/ or larger radiator. You might also use a 292 waterpump, it has a shield behind the impeller that directs water out away from the first cylinder.
