Which carbuerator is this and why does my air filter look so different?

[Dmulder]

[jeff10049]

looks like a SU HS4. You have a aftermarket air filter.

Jeff

[SomethingNew71]

I have that air filter on my HS2 dual carb setup.  It's a K&N filter.  Just cleaned mine recently, was super dirty haha.

EDIT:  I found a link to yours. It may not be K&N but it looks alot like one. 

http://www.minisport.com/mini-air-filter-hs4-su-carburettor.html

[Jims5543]

Yes, agreed, it is a HS4 carb. Here is a pic of my old and new next to each other with a K&N air filter. Looks to be the same as yours.