Need a little help with coil and plug wire selection. the motor are were 500 EfIs, just rebuilt them and now 509s whipple charged, still using 500efi ignition. my question is do i have to use the a stock coil with the merc setup or will a Msd one plug or work, and with the plug wires, its a stock merc cap thought about taylor 409 wires, or dui wires any thoughts on this, or any recamendatoins would be great....thanks for any help... Joe

You need to make sure your coil matches the output of your ignition system. If you read through the specs on coils, you will see a wide variance on input resistance and voltage. You could install a coil that requires more current than your ignition can handle, or have so much resistance that at the input voltage your ignition supplies that the output will be greatly reduced.