Intake hose size for newer Cobras

I just bought a twin 62mm BBK 'power plus' throttle body for my '69 mustang EFI conversion project, and I was wondering what size hose is used to connect the oval shaped throttle body to the intake piping. Its a replacement for a newer model cobra. Its going to be connected to a home fabricated intake pipe which connects to twin turbos. I'll make the outlet the same shape as the throttle body, I just need to know what hose to buy to use it. It measures 14.5" in circumference, which is about the same as a 4.6" diameter pipe. I'm guessing a 4.5" will fit snug, just making sure before I spend any money.