Whistling holley 1920

Well, @slantsixdan is an expert, so I would certainly listen to him. I do, however, have one more suggestion. Was the car idling fine? If not, there could be a slight air leak somewhere. Look for something that is loose. I had a friend with a Volarie SW with a slant 6, It was idling poorly, and making a sucking/whistling noise. I took the carb off and found that the bottom plate of the carb was slightly loose, I gave each of the 4 screws on the bottom about 1/2 turn, and everything was fine.
That is all I've got.