I am kind of suspecting the front carb. I thought I would try it with the 1/4 inch spacer to eliminate fuel perculation before pulling the carb apart. Suspiciously, it seems that my
oil level has increased slightly too - can't be sure as I may have just overfilled it slightly when I changed it.
I'm running a mechanical pump. I've felt all around all of the fuel line connections - I'm running all Ford reproduction fuel log, filter and lines. I haven't spotted anything underneath on the tank, fuel lines or hoses so far.
Fuel bowls on carbs are dry outside.
I don't think I should leave the vent on the fuel cap functional with a vented tank. I will try putting some tape over the vent hole before my next drive.
I think if the carb spacers and tape over the fuel cap vent don't do anything, then I will pull the front carb apart and see what I can find.