91-99 carb questions...

[Terry,OH]

For the 91-99 the vent is the oblong hole in the top cover casting see photo below. Your Carb. with the small round hole is not correct, but the hole should not effect performance. Later Carbs, although the tops are exchangeable have a vent tube in the top center of the Carb. they do not have the oblong opening nor do they need it.
The blocked hole is for the gas to enter the accelerator pump cavity. If it is blocked the Carb. may have been used on multiple Carb application, for one Carb. you want the hole open, so gas can fill the pump cavity. The bottom of the accelerator pump cavity should have a check ball as well as a retaining clip for the ball.