The best approach is to use an independent pickup circuit as suggested in post 7. The coil is replaced by a power resistor of a few to several Ohms, Pertronix wired in normal fashion. Black wire that goes to power resistor is trigger point, attenuate with 3 to 1 resistive divider with 5V clamp circuit. I can help with that stuff. Conditioning a coil primary signal is possible, but much more invloved to shave the ~400V peak and oscillations that follow.