The throat was 93% of the valve size but the valve job usually needs to be redone on these heads anyway. Port was 200cc and only flowed 266 cfm. A stock non-CNC port will flow about 250 cfm with a 170-175 cc volume. Mine will need a larger valve because of the throat size. With a larger valve it would probably be OK on a stroker, but I think it would be a dud on a street 340.