I personally prefer the Kaw system, but if you don't have the necessary components, the Dyna is probably easier to get together, and may be cheaper.
The Dyna S will use more power, and require 3-ohm or higher coils. If you are going to run extra accesories or lights, you may want to use the Kaw ignition system to reduce the draw on the charging system. You can use the 2.5-ohm coils on the Dyna S, but you run the risk of possibly damaging the Dyna S.
If your 750 had points, then it probably has 4-ohm coils, and would work well with the Dyna S, but not with the Kaw electronic ignition. Nevermind, 1980 KZ 750 H had electronic ignition.
I won't use 25yr old coils, since having been stranded by old coils after a rain storm. If they are original, I wouldn't trust them in the long run. If you buy new coils, 3-ohm coils will work well with the Dyna S or the Kaw electronic ignition.
I posted an updated diagram on your other thread:
here
Post edited by: loudhvx, at: 2007/11/13 03:09