Mystery carburettor

[bowjangles]

Any ideas on the year and model of this carb? It is a 4 bbl Nikki (I think). No identification marks anywhere that I can see. Very important that I find out, as I can't rebuild it without this info.
Carb is on an older 13-B that I can't date either. Both engine and carb were transplanted onto my recently purchased '80 Triumph tr-7.

[rxtasy3]

looks just like what a buddy of mine has. his came from a 74 rx4. i think they were Hitachi.