Prototype valves.
I found these in the pile of random goodness. Something didnt look the same. Smaller intakes and larger exhausts. Tim has been testing out some larger exhaust valves with some improvement. Id have to check installed spring height as these have the keeper grooves in a different location. Opening up the valve seats also gets sketchy as the this is the limit of the stock seat diameter . Ive installed larger seats before so thats doable.