Out of the roughly $175 worth of adapters I bought, this was the best. Unfortunately I did not realize there were left and right hand versions, so I had to place another order to get the ones I needed.
The non threaded side OD starts at 4-3/16" and the ID starts at 3-125/128". I have no accurate way to measure the taper as my calipers are standard size and will not reach. This side fits very nicely inside a 4" SDR35 fitting in the bell end.
The threaded size OD (minor diameter) is 3-115/128 and the thread (major diameter) is 4-1/32"