360 smog intake manifold

I have a 318 with 360 smog intake and heads. EGR valve holes on top of left side intake have been covered with a plate. The EGR holes in the heads by the exhaust manifolds have been plugged. That leaves the 2 holes in the floor of the intake below where the carb sits. Is it necessary to plug those 2 holes for the engine to run properly? Thanks for any help.