SNIP the more I think of your problem the more I am convinced that you need to eliminate the fuel supply as the potential problem. You could really get yourself down a rabbit hole without knowing for certain.
Mike
A fuel pressure gage tied into the lines feeding the carb's (mounted outside the cab for safety) - will quickly reveal a fuel supply issue.
I have not worked on a B carb for a long time .. is the needle and set big enough to keep up with a big main jet?
