i have an FBO coil. recommended voltage to the coil is 10-11 volts. the ru-11 .5 ohm gives me 8 volts, the mopar .25 ohm gives me 6 volts. i tested an MSD .8 ohm it was 7 volts to the coil. the stock 1.25 ohm was 5.5 volts to the coil.