Hitting the carb with a hammer causing the flooding situation to cease may indicate that the float may be contacting the casting nearby. It is pretty easy to bend those floats out of shape without realizing it.
Having said that, I will now illicit my "Its never the carburetor" mantra.
Popping from the carburetor and/or the exhaust upon acceleration is not indicative of a carburetor problem, but more likely a timing issue.
Either the timing is not set to specs, or something isn't right with the distributor internals, electrical or mechanical, or the timing gears.
The first thing that I would do is to verify that the needle is on the ball when the #1 cylinder is at top dead center.
Carl
