If it''s like mine, your Morgan you will probably have the crankcase breather (black box by fuel pump) which feeds gases back into the inlet manifold. You can buy a filler cap which has a hose 'take off' that you can vent to a catch tank. Haven't bothered on mine as not noticed a problem, although have bought a swanky Burton Power filler, and a posh rocker cover.
![[Linked Image]](https://tm-img.com/images/2019/04/06/_a6DAVY3zDwj17sw8Ak1G6R5id-49-fsCkCe64H6N6mdQY97VjyjHfi0gV1L8Sd9gukciOSyHaVhdDJVlbUe2oZBCuUi--EHgySKKQciITHI-Bi-wcfeI6KQsGWw3_yMkWsxbcprjmOsCkJJNX8fikTYar6GnFkGJEQilnQKP6s_KKogjMjxwVIglPLEUk-BAF6SKm23.md.jpg)
With regards to getting air into the carb, you'll probably have a Weber 32/36 DGV carb which will often already have a K&N style or equivalent, as in the picture. The smaller ones are rated for cars up to 100bhp, but you can get deeper ones for cars up 170bhp. Cost inder £100.