Porting question on exhaust bowl - pic attached

[92bird]

I disassembled a spare head today and was thinking of trying my hand in lightly porting a set.

The intake valve seat looks to be pretty well blended into the intake bowl in stock form.

The exhaust valve seat, not so much.. Is this a casting flaw of this particular head, or is this pretty typical? (see picture - seems the exhaust valve seat is smaller than the bowl.)

Obviously I can't just take the dremel/porting bit to the valve seat.

Is this something that a machine shop can taper in when doing a performance multi angle valve job? or is the only way to correct this by going with larger valves and seats?

Jeramie