hello B.B, the carby fitted to your 412 engine is correct. MK12/1,12/2 and the 412 were all fitted with the B.10 carby.the spec no 584x is a standard off the shelf engine. I have a spec listing for the 555x engine as scott bonnar,and the only special component was a different gov.spring, so I would assume that this engine also had the B10,carby.
regards, john.
