RE: 2 Klunk/Pump Setup
I think what you are getting at is called a Uniflow system.....
The way I have mine set up is ......
fill line.... capped off except for fueling...
clunked line to muffler pressure tap (no check valve)
clunked line to carb....
thats it... works perfectly...
The check valve might be an option to build up pressure...but you would need to unhook the fuel line somewhere while fueling....
Search for Uniflow... is that what you are refering to?