MGB / K&N air filter mod

I really want to enjoy the benefits of a K&N air filter but at the same time keep the engine looking standard.

The standard air filter box restricts air flow compared to the K&N set up so I drilled a series of 20mm holes all around the the base to minimise any restriction of air flow.

The K&N filter claims a gain of 2-3bhp on the MGB so hopefully that is still available.