"cold air intake" piping size

Made my cowl induction air cleaner from a used base and top that had a single snorkel that I got from a friend, Gary at Winkel auto in Milford NH. actually got the whole car as a project from him. Air cleaner takes a 13 x 3 3/8 air filter so I think it is from a big block motor. with the mouth cut down it fits under the hood. the tubes where made by hand by cutting and rolling some cheap thin metal shelving. tubes are ovalled, 4 1/2 by 3 inches. there was a little bit more volume of the thermoquad when it kicks in, not much more, but I like it!
air cleaner.jpg