If your plain is keep the carb mounted 90deree on the offey you will need more then the stock plate because the throttle arm will hit the intake.If you make your own plate go at least 3/4-1in thick and you'll be fine.a 4 port will keep a stronger signal to the carb.The idea behind the 4port over the open was to make the carb was sitting lowwer on the intake which ment more low end , Where as the open was more designed for higher rpm. If your deside to go with the open plate by all means remove the 4port on the intake.
my2cents is remove the 4port anyway and blend it.
God doesn't like ugly.
