Originally Posted by drostedrummer89
I would use as close to stock size as possible. I'm most worried about the small size of the thermostat to radiator, and radiator to water pump. If anything I would have gone bigger than stock. you are running 3-4X the horsepower, you need as much flow thru that radiator as possible.
If nascar vehicles use -16an lines from the pumps and for radiators and MAYBE sometimes -20an, I'm good!
This is from pump-to-radiator and radiator-to-thermostat: