Coil compatibility

The spark plugs will only 'take' the voltage they need to ionise the gap. What secondary voltage the coil is able to produce & what it DOES produce to ionise the gap.....are two different things. High end CD systems might dump 600v into the coil primary winding. If the coil's turns ratio is 100:1, then 60,000v can be produced in the secondary...but only 30,000v used.
Inductive ign such as points, HEI etc produce dump less voltage into the pri winding 250-400v so the secondary output voltage is correspondingly less.