MSD brain teaser

Hey guys I've tried everything I can think of to solve this issue I'm having so ill lay it out for u folks and please try to point me in the right direction. I've been running my 71 demon (318) with a 6462 msd btm ignition (will eventually go with boost) and blaster 2 coil along with a mopar distributor for a month or so now, and it ran great. I decided to switch the mopar unit for an msd 8388 distributor and blaster ss coil but once installed, I had no spark so after trying what I could think of to make it work I decided to cut my losses and put the mopar unit and blaster 2 back in but now that doesn't work either (still no spark). I get no spark from coil wire when touching the msd ign white wire to ground, as recommended by msd. I do have 12v switched at the red and verified, I do have 12v at the white when the key is in run position, and as far as I can see all wiring from battery, to ignition, to dist, to coil looks right. Is there anything that may have gotten messed up when pulling the old dist? What happens to the 2 old dist wires after msd install? Can I just go back to using the green and purple wires that I was using before insead of the white? I guess I could also use a refresher from someone about how the old ballast resistor wiring should look when done. I'm at a loss here guys and could really use the help, I don't get much time off work to enjoy the car so if really like to me mobile again. Thanks!!