Engine side Bulkhead Connector is stuck - any ideas?

1983 Dodge Rampage 2.2

Removed the 10mm bolt on the engine side of the 40-way bulkhead connector. Usually these pop right out with no problems, no resistance. This one is stuck like hell. I've been at it for hours with a pry bar, screwdriver, wd-40, yanking & pulling and it's gave about 1/8"... though i think i'm over estimating.

What gives? I have a spare engine-side bulkhead connector so I'm OK with this one getting destroyed. There's nothing in there as far as I can tell that isn't plastic-on-plastic. Except *maybe* the lock washer and t-nut got corroded together? that's not very much surface area and the bolt wasn't corroded...