Powerflow's carburetor is a Carter BBD, not a Stromberg WWC. The BBD came in two sizes: 1-1/4" venturi or 1-1/2" venturi. Small blocks used the BBD 1-1/4" and big blocks used the BBD 1-1/2". A 1966 383 would have been equipped with a Stromberg WWC. The 1966 361 was equipped with a BBD. Powerflow's carburetor is a 1968 or later unit because it has the hole in the throttle lever for a cruise control lost motion link.