New water header and breather tanks

The next plan was to remove the old Mini heater as it will almost never be required in Texas. It was always next to useless anyway. I also wanted to use the space the heater occupied for a new water header tank and a crankcase breather. I had originally used the left-over Fiat header tank, mounted on the heater box, as this is the highest place in the engine bay. While I never had any over heating problems, I'm not sure if it did its job or not, plus it was pretty ugly. With the heater gone I needed to make up a cover plate for the hole in the bulkhead and to mount the tanks. The breather tank came with 1/2" hose barbs, I am a bit concerned this diameter will be too small but we will see. With the water tank installed I can fill the cooling system. I have tried to research the best coolant for the twin cam engine. It appears Fiat originally specified Petronas Paraflu 11. And whilst it is still featured on the Petronas website, I cannot find a d...