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looks like a SU HS4. You have a aftermarket air filter.
Jeff
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
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.
(http://i6.photobucket.com/albums/y219/Jims5543/20140926_194935_zpssalhcc2a.jpg)