.75v drop through bulkhead??

That is "plenty." A more accurate way of doing this is by measuring the drop directly--you don't have to do any math.

Turn on the key to "run," engine off, if you have a points ignition make sure the points are closed. Do this by measuring the coil positive to ground. If it's close to battery, they're open. Bump the engine until the voltage falls low, anywhere from 4-8V, far below 12.

Then simply stick one probe directly onto the battery positive, the other on your dark blue "ignition run" (or ign terminal of the regulator) and read the drop directly.

This drop, by the way, ADDS to your charging voltage when running.

Most likely culprit is the bulkhead connector itself, so dig up a diagram and probe the engine side/ interior side of the bulkhead connector and see if that shows a drop. If not, next most likely is either the connector on the ignition switch, or the switch itself.

Don't forget to check the FEED to the ignition switch, AS IT TOO comes into the bulkhead and is subject to drop.

This is EXACTLY why so many of us advocate simply swallowing your Mopar pride and eliminate the connector by whatever means.

In some cases the so called "ammeter bypass" helps. In mine it did not. After the ammeter was bypassed the "dark blue" connector ALONE had a one volt drop from battery to ignition.