[MiraclePieCo]

Update: Plug 1, me 0.

I soaked it 24 hrs with PB Blaster, heated it with a torch (twice), then tried a series of removal tools: internal pipe wrench, pipe nipple extractor, air chisel, vice grips and spiral-style EZ Out. The EZ Out got the best grip, but I put MASSIVE pressure on it to no avail, probably just short of the extractor snapping off. The air chisel managed to mangle it but not budge it. There simply isn't room to get a drill, file or rotary burr into that area with sufficient visibility to avoid damage to the threads in the head. So...

The head has to come out. This is very demoralizing for me, as I was just ready to take the truck for it's first test run. Also the job would have been far easier when I had the front sheet metal off. With my schedule I estimate it will be about a month before I get back to square one now :-(