58mm Throttle Body

I have a newly built LT-1 383 Stroker with a 58mm Throttle Body. I was wondering where I can get an intake elbow (preferably a polished one) that will fit over the throttle body port since it is bigger than the stock one.

The "oval" portion of the throttle body is very close to stock, at least on my Holley 58mm. If the rubber elbow feels a bit tight, heat it in warm water to soften it a bit, then push it over the throttle body.