Well - we're back in business! Looks like the piston rings seized into place and the lack of suction wasn't getting the air/fuel mixture into the cylinder, then not compressing. She's running well now... finally.
Thanks to all for the input and help over the last months.
The new intake makes her run better than before, though the fueling above 8k rpm still isn't perfect. A Dyno would fix that, but she honestly doesn't need it and I'm pretty much done with her now as I'm outta time!