I have an OEM AVS on my 340. If I were to go ut right now and try to start it, it would crank and crank and crank because the float bowls are empty. It doesn't matter whether the last time I fired it up it got warm or not. Pour some fuel down the throats, it runs great (well, it might stumble while the fuel pump catches up). The fuel in that car is at least five years old (probably older).
I have heard that Holleys were less prone to the fuel evaporating so it might be leaking down the intake. Let it sit for three weeks and pull the carb for a look... (smell the oil, too)
