I got myself into quite the pickle. Finishing up a full resto on my 73 challenger. Running MSD 6al for ignition.Trimmed down the harness (engine bay side a bunch ) to clean up/ hide most the wiring. Got the car running and starting ran great (nose is still off). few days later still cleaning up wiring and saw a black wire coming from the engine harness that had a female bullet connector near the brake master cylinder. Just assumed it went to the proportioning valve. It fit right on perfectly. Well for some reason it was a hot lead and i ended up dead shorting that wire! it looks like it also branches off and on the other end is a female spade connector with two black wires running into the connector. I cant seem to find this wire on a wire diagram. It runs along side with the heavy red wire that goes to start solenoid.

So I unhook the shorted wire and go to crank the car. No spark. I guess of course i shorted my MSD box right?So I bought a new digital 6al box. Still no spark. I noticed i have now also lost power to the fuse block circuit during crank.
I hooked the 12v small msd wire to direct batt power just to see if i can get power to coil. Nothing. Replaced the dist mag pickup. No change. Made sure the dist is turning while crank,it is. I unhooked coil wire from dist. cap and shorted the purple/green mag to the msd and i get a very very powerful spark. Im not sure what im missing or where to look next. Any ideas i'd greatly appeciate!

this shows the black connector im talking about

/0/]black connector 2 wires

Well the MSD, the new one is OK. Fire comes in thru the bulkhead & the FL right there then goes inside & in/to/thru the ammeter then to a "welded splice" where it T's and splits & goes from there to the ign sw/some circuits in the fuse box/horn relay/headlight switch. I'd start from the back side of the bulkhead down to those areas searching for the open or opens

heres what im not understanding.

If the MSD is good and the car cranks over with ignition, what is preventing the coil from getting juice?

Does the mag pickup in the distributor tell the msd to power the coil? If the MSD small red is on constant 12V and the heavy red to batt, black good ground, white not used, coil blk/orange hooked up properly to coil and the mag from msd to dist hooked up shouldnt it have spark? what else does it need?

seperate circuits: starter circuit is fine, the coil and the MSD need fire in crank and in run. yes the dist (pickup) tells the MSD to fire the coil. its cranking & the MSD is good. all that is left is for the coil and MSD to be getting fire in crank and in run, check for opens starting at the bulkhead a frequent culprit & work forward or backwards from there. also the 2 wire circuit from the dist pickup needs to have no opens (not sure where it goes to on a MSD app). Short version: if you know you are wired correctly then grab your meter & find the open or opens. holler back later with any news

thank you! i will dig deeper and report back! Could this be the same reason why my fuse block is losing power during crank?

the ones that are hot as is shouldn't go completely dead and the ones hot when you turn the key to "on" then turning the key to start its then in ign2 (crank) to the upsream end of the ballast, the voltage then backfeeds thru the ballast & back into the blue wire ign1 (run) circuit the same way it'd be in ign1 "run" and anything connected to that blue wire circuit tho the ballast reduces it some plus the starter draw significantly reduces everything. while you're at it ohm the coil and the pickup, might as well cover all possibilities

Check the brown and the blue wires from the bulkhead. Ignition 1 and 2 , one is hot with key on and one is hot when key is in 'start' position . You may have to splice the brown and the blue wires together when bypassing the ballast resistor .

yeah this is correct, ign1 and ign2 need to be spliced together.

Fixed it. Reluctor gap was too big. Thanks for the help!