CREATE TABLE table_name_28 (bore_ VARCHAR(255), _stroke VARCHAR(255), carburetor VARCHAR(255), vin_code VARCHAR(255))
What are the bore & stroke specifications for an engine with 4-barrel carburetor and VIN code of A?
    
SQL: SELECT bore_ & _stroke FROM table_name_28 WHERE carburetor = "4-barrel" AND vin_code = "a"