3 Ohm or 4 Ohm?

Im working on a 1980 Kz550-A1 and im confused. My manual says use a 4 ohm coil but the Dyna Dual Output 3.0 Ohm Coils say they are Direct factory replacement? is 3 ohm ok or do i need 4 ohm? If i need 4 ohm can i put in a 1 ohm ballast resister and use the Dyna coils?

Thanks for the help!!

according to Kawasaki, the coils could be between 3-4.4 Ohms.
3 Ohms will give you a better spark and better efficiency but will make the CDI box run hotter. 4 Ohms will save on your CDI. Kawasaki also had a 2.2 Ohm coil for CDI ignitions 1981 on.

It has a point style ignition so this shouldnt be a problem right?

If it has points than it makes no difference at all. 3 Ohm coils will give you a bigger spark.

On the 550's, the points models (pretty much only 1980 kz550A) had 4-ohm coils. With a Dyna S you can use any coils that are 3-ohm or higher. As Otakar says, 3-ohms will give you better spark (at higher RPMs), but a 4-ohm coil will reduce heat and stress on the Dyna S igniter (not really a CDI, but is often called that mistakenly).

The Kawasaki factory ignition uses coils at about 2.4 to 2.6 ohms. These should not be used with the Dyna S (according to Dyna). The Dyna 3-ohm coils should work ok with the factory electronic ignition if you should ever upgrade to it.

The reason for the difference is that the points ignition uses a longer dwell than the factory electronic ignition. The factory electronic ignition uses hotter coils to compensate. The Dyna S uses a much, much longer dwell so can use even slower coils.