I wonder if that wide seat was purposely cut that way?I've found that the Thailand plant rarely cut the Most Important 60 degree angle on the exhaust valve seats to properly narrow the exhaust valve seat, seating surface for good sealing and long life.
Have you experienced the same fault?
A wider seat will transfer more heat from the valve to the head compared to a narrower seat, albeit at the expense of some loss of sealing ability.
Also, when folks grind the valve seats is there concern about sinking the valve too deep in the head? And what about valve stem length; is it/can it be trimmed accordingly?