[Healeys] Antifreeze

[Richard Kahn]

Sorry to bother the group with stuff that has been asked a dozen times but I
got a brain fart. I did this two years ago. The books say 18 pints of
antifreeze with out heater. I have a BJ8 with heater. That comes out to more
than 2 gallons of coolant.  How much coolant is needed with a heater? Are
there any preferences between Prestone premixed and  the type diluted 50/50?
Thanks
Rich Kahn