Changing a 12v - ignition coil input into a 12+ signal

[Bulletproofer]

Ok so to start off I am trying to change a 12v - input wire into a 12v + signal wire to change coils on an old motorcycle to use something cheap and plentiful like a Chevy ls ignition coil. Ideally I would only have a max input of about 6v+ going to the coil for a signal wire but I basically need the function of a relay (reversing the output polarity) but it has to cycle somewhere in the neighborhood of 2500 plus times a minute without a lot of delay and last for a long time. I know how to get a positive signal to it but I don’t know how to get that many cycles or switches on and off in a minute. Any advice or help where to go or what to do to make this work is welcome. TIA!

 

[Bluejets]

Your explanation does not make any sense...old coil type would be kettering ignition whereas new type would almost certainly be cdi, not interchangable.
Coils in the kettering system would be fed with, not a signal, but battery positive with the neg going to the points/condensor.
You cannot reverse that as the coil hv is referenced to ground.