I recently had the air filters off to do a repair on the carbs and got to look at the mod I did a few years ago on the filter lower parts to provide more air flow for K&N filters.
Many would say why not use the proper K&N filter plates …… but I just prefer a standard looking engine!
See my previous posts about K&N filters at …….. https://mgb.tips/category/engine/fuel-carbs/kn/
MGB tips mods and maintenance 