FYI, since so much internet info is speculative at best, I though a few factual measurements might help....shown are the coil drive current and the resultant max spark output. cheers Dave Comeau Boyer MKIII analog: 13.5v drive A. 2-12v lucas coils 45223A in series @1.4 Amps, 17-19kv B. 2-12v lucas coils 45221A in series @1.4amps, 17-18kv C. 1-12v dual output Standard Motor Products-Blue Streak SHD1X @1.65amps, 42kv gross(reduce by 3kv for wasted spark) 39kv net D. 2-6v lucas coils 45220A in series @2.1 amps, 23-24kv E. 2-6v PVL 101215 in series @2.1 amps, 24-26kv F. 1-12v dual output Accel 140403 @2.2amps, 37kv gross(reduce by 3kv for wasted spark) 34kv net G. 2-12v lucas coils 45223A parallel @3.6amps, 13kv H. 2-12v lucas coils 45223A parallel @3.6 amps with isolation diodes, 24kv