I have the Blue RUN wire and the single Brown START wire connected together and it started and idled fine except for the ammeter/battery gauge/MSD 12v feed guages going berzerk.
Then I tested the twin brown wires and they both showed 12v START and 12 RUN also which I thought was weird.
Thanks MR. P. and 70
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""I think I'd jump the MSD directly from the batt positive and negative posts""

My first test was having the HEAVY RED wire from the MSD box going to my 40a fuse that comes off of my starter relay. The gauges showed bouncing. Then I tested it again with this same wire going to my positive battery post cable and the gauges showed the same thing.
I have the HEAVY BLACK wire going to my intake where I have three body grounds mounted together on a bolt. I will try to take this same wire to the negative battery cable to see if this makes a difference. Maybe my main ground going to the intake is the issue.

Thanks allot.

1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)