[pat_c_52806]

Just fired up for the 427 first time in the car. When the ignition switch is turned off it keeps running, had to pull the coil wire. Never had this problem before I replaced everything under the hood and bumper to bumper. I don't think it's the ignition switch. Am running 6al with billet dizzy.

[JimM]

check msd.com, they have a diode kit to prevent that problem.

[prostreet69camaro]

Yes you have to put a diode on one of the wires from the alternator. With the motor running and alternator turning it is keeping power to your MSD box and will not let the motor turn off. Do like Jim said and go to MSD.COM. They have a troubleshooting forum on their website.

[PROZ11]

I had that problem on my last car with MSD. Instead of the diode, I just put a heavy duty toggle switch on the main power lead for the MSD box. I hid it under the dash so it also doubled as a kind of anti-theft device.

[pat_c_52806]

Yeah I put a diode in line in the right direction and the dam thing keeps on running. I might give msd a call.

[dnult]

Sounds like your switch 12v wire (small red wire I believe) is hooked to B+ instead of IGN. However the big read wire should be connected to a fused B+ source.