Maybe I missed it, but have you told us all of the stuff you did check? Might be easier than us guessing what it could be.

Looks like your missing about 200 hp.

First thoughts:
If the car has mufflers, something sh** the bed there
What's your trap fuel pressure?
Cranking cylinder pressure?
Cylinder leak down?
Converter sh** the bed
Fuel line problem between gauge and carb
Cam timing off
Ignition timing way off
lost lobe

I know in the past that I have been so convinced that something was right that I could not see that it was not.