Stalls with electrical loads

Spent some time troubleshooting this weekend:

Voltage Drop at firewall with accessories on and running ground checked out:

Same at ground on radiator support:

Voltage drop at run terminal:

Voltage at coil:

Plenty of juice at idle in neutral:

Not shown but dropped below 12 volts in gear with accessories on, never dipped below 11.5 volts. After swapping carbs again I noticed how much more throttle it took to maintain idle than on my 350 Chevy which has same cam specs as the Mopar. Carbs have same jetting, not that it matters much at idle or at least it shouldn't . I pulled each plug wire while running, no dead cylinders found. Next step is to check the T-Slot. Did notice after swapping carbs again that it took allot more idle throttle than the donor 350 Chevy engine took to run on it. Both engines have same cam spec and similar set ups. Both carbs hesitated slightly on ported vacuum with this car, perhaps because of over exposed T-Slot. Neither carb hesitated on the 350 Chevy. So next step is to pull the carb again and check that out too. You may be on to something A J.