71 LA 340 timings moved!! how?? looking for help

You don’t want any type of ballast with any msd coil unless specified by msd. You may have just gotten lucky with the blaster 2 coil. I looked on msd site, the blaster 2 and 3 have the same number of coil turns. Maybe the 2 is an older model and truely has a different number of turns, maybe not. Either way, shitcan or bypass the ballast for testing and set total timing to 33-35 and let us know