Which Pertronix coil for my 340?

Had afew conflicting reads on which coil to use on my 1970 340 ,its got the igniter 2 dizzy n a pertronix igniter2 0.6 ohm coil ,no ballast resistor(removed).Coil is done and i want to be sure 0.6 ohm is correct or should it be 1.5 ohm as they sell both?Thanks