Re: tri power for a bbc?
the vent tubes just make it harder for gas to slosh out of the bowl during hard stops or bumps. If you're not having problems with slosh killing the engine during hi-G events you don't need the tubes.
If you have the tubes and they're close to the air filter lid it can cause weird fluctuations in the air pressure in the bowl leading to unpredictable mixture changes, usually under heavy load/heavy throttle where there's a lot of air moving across the tops of the tubes.
As said, if you're not having problems then nothing needs "fixed."
Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.