Not getting 12v to coil on start ('73 Dodge W200 360La)

You pulled this off the "start" wire? Be careful that will try and backfeed. The coil circuit will try and engage the start relay in park or neutral, and "draw down" the coil voltage if "NOT" an MSD You might have to put in a series diode in the new wire. About 10A 24 or more PIV to be safe
I really appreciate all your help; I have read a ton of these forums and learned a bunch from your hundreds of comments. I've been driving my truck since I was 16 (5 years now!) and although still a novice, I have learned a ton. I messed around with the wiring some more and was able to hook up the stock coil wire to the msd box. I have been dding it for the last few weeks with no problems. There may still be a gremlin in the wiring, but hopefully replacing the altenator wire and bypassing the ballast (since I changed from a real 5 pin ecu to a 4 and was running it through a dual ballast) fixed my problem. And for the future people like me, don't hook a blaster 2 coil directly to a stock ecu, and use a ballast with a stock system.