define more efficient, it is non restrictive and extremely efficient :) nothing to slow the incoming air, think most are running NO air cleaner as they were removed at some point, and hard to come by for these early Chevrolets.
it does not really CLEAN the incoming air. basically an tuna can, also the roads today are far better (paved) then they were back when these vehicles were built (dirt).
i know that some people that have concerns of debris getting into the carb have used some steel wool and coated it with oil, and stuffed it in the air cleaner, not to tight or dense, has to breathe !! similar to how they did it on later years. just have to remove the cleaner and flush it out and recoat it every so often.
I have a 29 and a 30 running both stock air filters for several years now with no issues. i would have some concern IF i was driving dirt roads or through fields, but every day driving on city roads not really.
