If you take your heads to a shop and have a valve job done, you very well could get something like this.
20160810_131010 (Medium).jpg
Then opened up the ID of the seat, and blended to the next angle once the width was better.
20160810_153045 (Medium).jpg
Flowbench testing
20160810_154533 (Medium).jpg
Results
ExhaustSeatComp.jpg
20160810_131010 (Medium).jpg
Then opened up the ID of the seat, and blended to the next angle once the width was better.
20160810_153045 (Medium).jpg
Flowbench testing
20160810_154533 (Medium).jpg
Results
ExhaustSeatComp.jpg