/6 rebuild advice

GRAB the carburetor by the very top of it and twist it back and forth. Pay close attention if it moves either on the manifold, OR if it moves independently of the base plate, just look for any movement at all. It's very common for the gaskets to shrink over time and this will loosen the fasteners that hold the carburetor on the intake as well as the screws that hold the carburetor together. Lots of times you can tighten everything up and it will make a world of difference.